Wyatt Fuller is the son of jewelry designer Quinn Fuller and Bill Spencer, Jr., with whom Quinn had a long-ago affair; Wyatt grew up believing his father was dead. Wyatt met Hope Logan when she photographed him taking a solar shower at his campground in Big Bear, California; Wyatt impulsively kissed Hope, who had run away and knocked herself unconscious. Though Hope lamented the absence of her on-again-off-again paramour, Liam Spencer, who was working through being deserted by his wife, Steffy Forrester, Wyatt introduced Hope to Quinn, unprepared for the shock when Hope figured out that Bill was Wyatt's father by matching up the identical sword necklaces they wore. Wyatt felt betrayed by Quinn and was furious with Bill for having given his mother money for an abortion.

Wyatt briefly entertained taking both Hope and Spencer Publications from Liam, but soon he focused solely on Hope; Wyatt kissed Hope, earning Liam's fist in his face. Wyatt thrilled when Hope decided to incorporate Quinn's accessories into Hope's Hope for the Future (HFTF) fashion line at Forrester Creations, and gladly followed Quinn's order to take Hope to Mexico to secure a rare diamond. Surprised when Quinn sent Hope a video tribute Liam made for Steffy, Wyatt used the resulting rift to propose to Hope himself, then pocketed the diamond and placed it on actual jewel thieves he pretended to retrieve it from.

Wyatt dated Hope after she dumped Liam for having a secret meeting with Steffy on their wedding day. Wyatt made love to Hope for the first time on a beach camping trip, his reverie broken when Liam arrived with security footage of Wyatt "stealing" the diamond. Wyatt was dismayed when Hope left him standing on the beach, but later, after Hope took him back, Wyatt's theft was buried by Forrester Creations to prevent a media scandal.

Wyatt wanted to honor late Forrester matriarch Stephanie Forrester by tying her personal jewelry into HFTF, but Stephanie's granddaughter, Aly Forrester, who had a history of mental illness stemming from the violent childhood death of her mother, loudly objected. Wyatt dismissed Aly's contention he was corrupting the message of purity Hope had layered into HFTF and was slapped by Aly for bragging he'd slept with Hope; Wyatt worried when Aly caught him in bed with Hope and threw a tantrum.

Wyatt was disappointed when Hope's pregnancy scare was only that, but more so when Hope agreed to date both Spencer brothers. Wyatt lost Hope when he punched Liam for going off on Quinn, whose attempts to come between Bill and Brooke Logan, Hope's mother, ended with Brooke's ex-husband, Ridge Forrester, falling from a helicopter in Abu Dhabi and sustaining brain damage. Hearing that Quinn had been tormenting Liam to keep him away from Hope, Wyatt barely stopped Quinn from impaling Liam with a sword. Wyatt and Liam bonded over the ordeal, and later Wyatt received a text from Quinn in which she said she had checked into a psychiatric hospital.

Wyatt inherited the HFTF diamond from its owner, Ricardo Montemayor, and publicly presented it to Hope. But when a detective told Wyatt that Ricardo had been murdered, Wyatt briefly wondered if Quinn had been responsible. Wyatt flew to Paris with Hope, who had told Liam to meet her at the Eiffel Tower to get married. When Liam didn't show, Wyatt convinced Hope to marry him in Monte Carlo instead. Wyatt was sure Hope would leave him when they found out Liam was late was because Quinn had pushed fellow jewelry designer Ivy Forrester into the River Seine; instead, Wyatt got news that Hope was carrying his baby.

Wyatt grudgingly considered getting a restraining order against Quinn, who kept insinuating herself into the pregnant Hope's life; when Hope fell down a flight of stairs and lost their baby after arguing with Quinn, Wyatt sadly watched as Hope went on an extended trip to Milan, Italy. Wyatt followed to plead his case, but came back with a divorce. Wyatt frowned on Quinn's relationship with Hope's father, Deacon Sharpe, knowing Deacon still had a thing for Brooke, and went straight to Quinn after hearing Deacon tell Brooke he'd reunite with her if he and Quinn weren't engaged. After Quinn and Deacon worked things out, Wyatt was the only guest at their wedding except for Hope, who chimed in via video call in an unsuccessful attempt to stop the ceremony.

Wyatt teamed up with Liam to force tyrannical Rick Forrester out of Forrester's CEO chair. Sensing a secret surrounding Rick's mistress, Maya Avant, Wyatt romanced Maya's inexperienced little sister, Nicole Avant, for information. Wyatt genuinely liked Nicole, but worked on her until she admitted Maya was transgender. As Wyatt and Liam deliberated over what to do with the revelation, publishing magnate Bill splashed it across his media platforms; Wyatt understood when Nicole declared she'd never trust him again.

Wyatt took an interest in Steffy and kissed her despite her desire to reunite with Liam; eventually Wyatt began dating Ivy. After the increasingly unstable Aly regressed and died confronting Steffy, an incredulous Wyatt viewed a video Ivy shot that seemed to show Steffy killing Aly with a tire iron. Feeling marginalized by their families, Wyatt supported Ivy using her video to blackmail a modeling gig out of Steffy; later, Wyatt thought better of it and helped persuade Ivy to delete the incriminating footage. After Steffy fired Ivy, Wyatt went to Bill with a request to bankroll a new fashion house and was angry when Bill declined.

Wyatt resented Steffy's brother, Thomas Forrester, for flirting with Ivy and refused to believe Steffy's claim that Ivy had kissed Thomas. Wyatt walked out when Ivy confirmed it but rushed to her side when she was electrocuted following a scuffle with Steffy. Wyatt talked Ivy out of having Steffy arrested for violating her restraining order, then bought a ring for Ivy. But Wyatt's proposal was interrupted by Quinn, who overheard Ivy telling Liam she wanted him back. Wyatt sent Ivy packing and cuddled Steffy in bed while Liam escorted Ivy back to Australia.

After a missing Liam sent Steffy text messages ending their relationship, Wyatt kissed Steffy and soon asked her to marry him. After their ceremony on the beach, Wyatt saw Forrester security footage of Liam hitting his head in the parking lot and Quinn driving off with him. Wyatt visited Quinn at her cabin and caught her kissing an amnesiac Liam, sickened when Quinn admitted telling Liam they were husband and wife. Wyatt's presence gave Liam total recall and Wyatt helped Liam lock Quinn in a closet and escape, but the resulting goodwill between the brothers quickly faded when Wyatt told Liam he'd married Steffy, whom Liam wanted back.

Wyatt made Steffy a queen of social media and promised to keep Quinn away from her; unfortunately, things fell apart when Quinn got involved with Steffy's grandfather, Eric Forrester. Wyatt stood by Steffy in a boycott of Quinn and Eric's wedding, but saw how much his mother loved Eric when Eric collapsed from a brain hemorrhage. Wyatt lost Steffy after he told Quinn that Steffy and Ridge were keeping it secret that Eric had given Quinn his power of attorney. Put into Steffy's orbit when he became head of PR at Forrester, Wyatt hoped to save his marriage to Steffy but ultimately agreed to fast-track their divorce so Steffy could marry Liam in Australia. Wyatt quit Forrester and returned to Spencer, but not before a drinking binge where he vented to Nicole and her husband, Zende Forrester Dominguez.

Wyatt threw himself into work and developed a camaraderie with Liam, playfully sassing Bill. But Wyatt tended to be on Bill's side in his crusade to acquire recently rebooted Spectra Fashions and replace it with a skyscraper. Wyatt was upset to learn someone had been shooting at Quinn and couldn't believe it when the gunman turned out to be his former stepfather Deacon. With Katie taking over his PR job at Forrester, Wyatt gladly gave her pointers about social media and created what ended up being a swimsuit fashion duel with Spectra in Monte Carlo; overseas, Wyatt and Katie kissed, with Wyatt assuring Katie their connections to Bill and Quinn wouldn't be an issue. Wyatt won Katie over after he rejected her attempt to set him up with a besotted intern, but it was all he could do to help Katie keep their no-strings relationship from Bill. However, Wyatt received a shock when Quinn found out about Katie and dragged her out of bed.

When Liam suddenly took control of Spencer Publications, Wyatt did some sleuthing and learned Liam had bought Spectra Fashions, which had recently suffered fire damage, and presented it to rightful owner Sally Spectra. Wyatt found out Bill had torched the building to take it from Sally but still defended Bill to Liam. Wyatt declined Liam's offer to run Spencer with him, warning Liam that Bill would seek revenge for taking the company. Wyatt was surprised when Bill made up with Liam and installed both his sons to run Spencer with him, only to find out he'd merely been positioned to vote with Bill against Liam regarding Spectra Fashions' demolition. Wyatt felt horrible when Liam and Sally were injured in the wreckage of Spectra, which Bill had blown up, not knowing they were inside.

Wyatt nearly abandoned Bill when he found out Bill had slept with Steffy. Wyatt had an uncomfortable reunion with ex-wife Hope, who had returned from Milan, then saw Katie kissing Ridge's brother, Thorne Forrester. After Wyatt broke up with Katie, he realized his feelings for her were deeper than he'd admitted, so Wyatt asked Katie to be his wife. Wyatt's happiness was short-lived once he told Bill about the engagement and Bill threatened to disown Wyatt; because Wyatt swore that would be the last thing Bill ever did, Wyatt became a suspect when Bill was shot in the back by an unknown assailant. Wyatt was sure that Bill's right-hand man, the power-hungry Justin Barber, had done the deed.

Wyatt accepted the recovering Bill's offer to become CEO of Spencer in five years if he left Katie, yet continued to see Katie in secret; Wyatt felt he deserved it after how badly Bill had treated him. Wyatt walked in on a post-seduction scene in Bill's office and told Liam about Bill's apparent continuation of his affair with Steffy, which caused Liam to propose to Hope. Wyatt discovered the "affair" had been a ruse and accepted expensive bribes from Bill to keep quiet until his conscience got the better of him; Wyatt interrupted Liam's wedding with the truth and found himself cut off by Bill for real.

Because Katie's little son, Will, was confused about the relationship between his mother and his half-brother, Wyatt, Wyatt reluctantly agreed with Katie's decision to break things off. Wyatt drowned his sorrows in a bar and came across the now-homeless Sally; Wyatt let Sally sleep on his couch but had to talk her down when she pointed a gun at him over his connection to Bill, whom Sally blamed for ruining her life. Eventually, Wyatt and Sally entered into their own relationship, which did not thrill Quinn; Wyatt did manage to talk Eric into hiring Sally on at Forrester. Wyatt commissioned artist Zoe Buckingham to paint a mural in his house, not knowing Zoe was using Sally's laptop to post threatening messages on the Hope for the Future web site in an attempt to harass her romantic rival, Emma Barber. Wyatt defended Sally vociferously when Sally was wrongly accused of the cyberbullying.

Wyatt testified on Bill's behalf when Katie took Bill to court, suing for full custody of Will. Later, Wyatt was rehired to do PR at Forrester, which pleased both Sally and Quinn. Wyatt cheered for Sally when Steffy signed her to design lingerie for Forrester's Intimates line, and eventually Wyatt told Sally he loved her, happy that Sally reciprocated his feelings. Later, Wyatt agreed to return to Spencer Publications, but only if Bill revived Spectra to make up for destroying Sally's career. Though Wyatt was thrown when Bill insisted on naming the new fashion house Spencer Fashions instead, Wyatt and Sally allowed it; Wyatt was happy to finally be reconnecting with his father.

Wyatt was disappointed when Sally decided to stay at Forrester, having gotten a better offer from them. Wyatt ran into Florence Fulton, his high school sweetheart from Las Vegas, and finally got a chance to apologize for suddenly leaving town because of one of Quinn's shady business arrangements. Wyatt introduced Flo to Sally, then helped Flo submit an online DNA test because Flo had gone her whole life not knowing who her father was; Flo ended up being the daughter of Katie's deceased brother, Storm Logan.

Wyatt became suspicious when he started seeing Sally hanging around her ex, Thomas. Confronting Sally, Wyatt learned that Thomas had confided in her a plan to win Hope, who had lost Liam's baby, and make her a mother for Thomas' son, Douglas Forrester, who had just lost his mother, Wyatt's cousin Caroline. Despite his outrage over Sally having kept an important secret from him, Wyatt did not divulge that he had kissed Flo behind Sally's back; when Sally moved out to give Wyatt space, Wyatt went to Flo and suggested they were being given a chance to pick up their teenage romance where it left off. Before long, Wyatt decided to move Flo in with him and declared to Sally that their relationship was officially over.

Wyatt agreed to help Liam when he declared he had overheard Flo and Thomas arguing about a secret that involved Hope. Wyatt tried to get an increasingly emotional Flo to open up and reported back to Liam when Flo oddly said she had never given birth, despite everyone knowing Steffy had adopted the baby Flo had given up. Wyatt reeled when Flo finally confessed she had been part of a cover-up started by Reese Buckingham, an obstetrician who stole Hope's baby, switched it with a dead one, and used money from Steffy adopting her to pay gambling debts. Wyatt immediately apologized to Sally for coming down so hard about her own secret-keeping and eventually proposed, though he was impressed that Flo had donated a kidney to an ailing Katie to help make restitution to the Logan family.

Wyatt was greatly disturbed when Sally called him "Liam" out of nowhere; Wyatt broke off his engagement to Sally to reunite with Flo. But soon Wyatt learned from Katie that Sally was dying of a terminal illness, so, encouraged by Flo, Wyatt invited Sally to move in with him. Wyatt tried to get Sally to confide in him about her illness and only got confirmation of her death sentence when Sally's physician, Dr. Penny Escobar, paid them a visit and pressed Sally to tell Wyatt the truth. Wyatt was in disbelief when Sally said she'd only seek treatment if he came back to her.

Wyatt came home to find his living room in disarray and worried when Sally, who had been using a walker, said she had tripped. Wyatt was on the fence about granting Sally's dying wish to make love until he saw “help” written on her underwear in Flo's writing; Wyatt ran to Sally's and found a kidnapped Flo tied to a radiator. After Sally collapsed from a panic attack, Wyatt agreed not to press charges, but advised Sally find herself, far away from him and Flo.

After Quinn was thrown out by Eric for nearly succeeding in breaking up Ridge and Brooke's marriage, Wyatt immediately regretted it when Flo invited Quinn to stay with them without running it by him first. Later, Wyatt arranged a publicity deal for Summer Newman, who ran the Jabot Collective in Genoa City, Wisconsin; when Summer visited, Wyatt could tell Summer was looking for dirt on Sally, who had moved to Summer's town, which prompted him to keep mum on his ex's many misdeeds.

Seeing that Flo still felt cut off from the Logans, Wyatt went to Katie, Brooke, and their sister, Donna Logan, and convinced them to forgive Flo for her part in Beth's illegal adoption. Wyatt then topped Flo's being allowed to take the Logan name by asking Flo to marry him. But Wyatt became concerned when he kept walking in on Bill and Liam in obviously tense situations. Later, Wyatt's suspicions were confirmed as Bill and Liam went to jail for covering up a hit-and-run involving Thomas' best friend, Vinny Walker; it was later revealed Vinny had thrown himself in front of Liam's car on purpose to frame Liam and free Hope up for Thomas.

Wyatt took Bill to a shoreline seafood restaurant and was confused when he later found out that Bill had taken a mute homeless woman he had discovered in its alley back to his house. The woman was Li Finnegan, who revealed that her presumed dead son, and Steffy's husband, John "Finn" Finnegan, was indeed alive. Later, Steffy's mother, Taylor Hayes, bought the home in which Wyatt lived, which was owned by Bill. Wyatt became concerned when Bill got into a romantic relationship with criminal psychopath Sheila Carter, who, among other things, had shot Finn and Steffy; Wyatt teamed up with Liam to get through to Bill, but they were unable to move their father. Wyatt was floored when Bill later admitted that his relationship with Sheila had only been a ruse to goad her into confessing to a long-ago murder.

Wyatt continued to be a sounding board for Bill and Liam, but ultimately exited the canvas without an explanation. A few months later, Wyatt made a brief return to sublet his beach house to former brother-in-law R.J. Forrester, and to encourage Bill to pursue Poppy Nozawa, a woman Bill had known many years earlier.