Bill Spencer, Jr. is the previously unknown son of publishing magnate Bill Spencer, Sr. They had never been close, but when the elder Spencer died, Bill came to Los Angeles to carry out his father's last wish: to avenge his one true love, Stephanie Forrester, by destroying Eric Forrester and Forrester Creations. Bill encouraged Stephanie, who had defected to rival fashion house Jackie M, to rant about the Logans in a damaging video blog. Eric refused to sell Forrester to Bill, who blackmailed Eric with the knowledge that Eric had hired an illegal immigrant years ago. But Stephanie recorded the conversation and threatened to go public unless Bill backed off.
A consummate womanizer, Bill put the moves on an unresponsive Donna Logan. Later, Bill met Donna's sister, Katie Logan. Fresh from a breakup with Nick Marone, Katie got drunk at the Cafe Russe, but Bill chose not to take advantage of her. Instead, Bill got to know Katie, who challenged Bill's tendency to be a shark. When Katie found the DVD of Bill's father laying out his mission to Bill, Katie questioned Bill's growing feelings. But Bill insisted his devotion was genuine, and proposed. Bill knew Katie wanted to do something special after a second chance at life via a heart transplant, so when Bill finally secured Forrester Creations, he made Katie its CEO. Young Steffy Forrester was intrigued by Bill and kissed him. But Bill still married Katie in her old San Fernando Valley neighborhood. Resenting Bill's control of their company, the Forresters unsuccessfully tried to sabotage Bill by creating the ugly Dare fashion line. Steffy took things one step further and used Bill's attraction to set up a seduction. Bill bit, but Steffy put on the brakes and stole Katie's engagement ring from Bill's bedroom. Steffy threatened to show it to Katie if Bill didn't sign Forrester over to Steffy. Bill fumed and vowed revenge, but secretly admired Steffy's ruthless behavior. Bill befriended Donna, whose marriage to Eric was in trouble, and suggested Donna ask for half of Eric's Forrester stock in the event of a divorce. Bill began to think of the Logans as the family he never had, offering to join forces with Stephen Logan against Eric and blasting his right-hand man, Justin Barber, for exposing Brooke's "mistaken identity" sex to the world. But later, Bill had no problem exposing Brooke's daughter, Bridget, when she had her own paternity scandal, saying he'd already given the Logans "a free pass." Bill also convinced Donna to sell him the 12.5% of Forrester she'd gotten from Eric, and tried to buy an additional 25% from Steffy.Liam Cooper, an intern at Spencer Publications, revealed that his mother, Kelly Cooper, had died and sent him to Los Angeles in search of his father. Kelly had dated both Bill and Thorne Forrester, who insisted on a DNA test. Bill scoffed to find he had a son in the forthright Liam, but Katie encouraged Bill to develop their father-son bond. Bill wanted Liam to man up and disapproved of Liam dating the gentle Hope Logan, so Bill tried to press Hope's ex-boyfriend, Oliver Jones, into winning Hope back. Failing that, Bill arranged a coming-out party and introduced Liam to the press as "the world's most eligible bachelor," which made Liam uncomfortable. Bill backed off and accepted Hope.
Bill went ballistic when Amber Moore claimed that Liam was the father of her baby. After Amber's mother, Tawny Moore, managed to fix the paternity test, Bill offered Amber $500,000 to leave town. But Amber wanted more, so Bill bought a cliff house that had a faulty balcony and moved Amber in, hoping Amber would fall to her death. Steffy returned from working in Europe determined to have Bill for herself, and caught Bill luring Amber to the edge. A tree branch fell, almost doing the job for him, but Steffy saved Amber. Katie walked out when she discovered Bill's plot, but Steffy told Bill she "got" him and was better for him than Katie, who demanded Bill seek therapy.
Bill snarked his way through sessions with Steffy's mother, Dr. Taylor Hayes and seemingly made up with Katie off-screen.. But when Steffy's brother, Thomas, went missing at sea, Steffy begged Bill for help. After Bill used his resources at Spencer to rescue Thomas, he reciprocated Steffy's declaration of love. Steffy had family problems and leaned on Bill for support, igniting a full-blown affair. Taylor caught them before they could make love and kicked Bill out of the house. Bill was ready to leave Katie, who surprised him with a vow renewal ceremony. But Katie had a heart attack when Taylor told her about the affair, and Bill chose to stay with Katie. Steffy was devastated, but fell for Liam after he saved her from drowning in her bathtub.
Steffy's father, Ridge Forrester, punched Bill over his involvement with Steffy, so Bill went to Nick with an offer to buy 50% of Jackie M in order to crush Forrester. Nick was tempted, but Nick's mother, Jackie Marone, ultimately nixed the deal. Bill again deemed Hope unsuitable for Liam, so he teamed with Steffy to get rid of Hope. On Bill's orders, Steffy kissed Liam at Liam's bachelor party. Hope saw it and left her engagement ring on Liam's mantel. Liam offered the ring to Steffy, and Bill capitalized on it by sending Steffy and Liam to Aspen. When Hope followed, Bill arranged a wedding for Steffy and Liam, which Hope was forced to watch while trapped in a gondola, courtesy of Bill.
Katie was outraged when Bill gave Steffy a seat on the Spencer board and planned a "family vacation" to Cabo San Lucas. Bill stayed behind, helping from the sidelines when Hope and Thomas ended up at the same resort as Steffy and Liam. But Hope and Liam saw each other, and Steffy was injured in an ATV accident. Knowing that Liam wanted to return to Hope, Bill fixed Steffy's MRI to say she had a life-threatening blood clot that could worsen under stress. Liam felt obigated to stay with Steffy. Katie got suspicious, and soon uncovered Bill's plot. Bill locked Katie in a tower to keep her from exposing him, but when she escaped and told Liam, Bill found himself alone. Hope threatened to go public with Bill's crime, but never made good on it. Bill and Katie again resolved their issues off-screen, though one night Bill fantasized about Brooke during dinner.
Bill's half-sister, Karen Spencer, paid occasional visits from New York, but relocated to Los Angeles when her daughter, Caroline Spencer, took a job at Forrester. Bill raised an eyebrow when he met Danielle and assumed she was Karen's roommate. Fearful that Bill would be homophobic, Karen was adamant that Bill not find out Danielle was her spouse and that Caroline was their daughter, even as Karen arranged a job interview for Danielle at Spencer. Bill was intrigued by Danielle's international exploits as a freelance writer and thought that Danielle was coming on to him. But when Karen finally explained about her relationship with Danielle, Bill gave Karen his acceptance.
Discovering that Hope was taking antianxiety medication to cope with the press labeling her an adulteress, Bill stepped up his anti-Hope campaign and arranged for Hope to be besieged by paparazzi in Aspen. The scheme netted Bill a photo of Hope popping a pill, but Bill didn't use it. Instead, Bill sprung Hope's father, Deacon Sharpe, from jail as part of a plan to prevent Liam's wedding to Hope in Puglia, Italy. The scheme almost worked, but when Liam married Hope anyway, Bill publicly apologized to Hope and accepted her into the family. However, the union didn't last, and when Liam showed up to his do-over wedding with dyed hair and a tattoo after a night of clubbing with Steffy, Bill berated Liam for begging Hope's forgiveness on his knees wearing only underwear, and demanded that Liam start acting like a Spencer.
When Katie told Bill she was pregnant, Bill insisted she get an abortion. Bill later softened and admitted he was only afraid Katie would die trying to carry a baby to term given her heart condition, and warmed to the idea of having another son. Later, Katie found Deacon in Bill's office, and the truth about Bill's misdeeds triggered Katie to go into an early labor. Bill found himself making an impassioned prayer in the hospital chapel as Katie flatlined on the operating table. Katie recovered, but couldn't forgive Bill for breaking the law and putting their family in danger. Bill told Donna and Brooke about Deacon when Katie slipped into postpartum depression; the sisters only agreed not to prosecute Bill for the sake of Katie and baby Will. Afterwards, Bill threatened to have Deacon killed when Deacon tried to blackmail Bill into giving him a job at Spencer.
Bill was mystified when Katie disappeared. He and Brooke followed clues to Aspen, where Bill found an envelope with Katie's wedding ring and a note asking for a divorce. Bill was sad, then angry; Brooke was worried that an unconscious Bill had committed suicide when she found an empty bottle of pills beside him, but he was only taking a nap. Bill and Brooke, who had just lost Ridge, comforted each other, and were surprised by a hot-air balloon ride that was arranged for them. They didn't know that Katie, in her melancholy, was paving the way for Brooke to replace Katie as Bill's wife and Will's mother.
Brooke was devastated when Stephanie died at the Big Bear cabin. Bill arrived to comfort Brooke, which led to a kiss. Afterwards, they were shocked to find Katie back home and ready to reclaim her life. Katie admitted to a guilty Bill and Brooke that she had been trying to set them up. Bill and Brooke swore each other to secrecy about the kiss, but Taylor overheard and told Katie about it. Bill and Brooke swore the kiss meant nothing, and Katie forgave them.
Meanwhile, Caroline overheard Bill and Katie discussing how he used Deacon to sabotage Hope and Liam's wedding. Caroline confronted Bill, who menacingly told Caroline he wouldn't let her tell Liam the truth. When Caroline accidentally fell over the balcony during the argument, many suspected Bill of pushing her.
Bill brushed it off when Katie smelled alcohol on his breath at the hospital, but was aghast when Katie, Brooke, Taylor, Karen, and Danielle staged an intervention on him. Bill disagreed when Katie insisted he made bad decisions when drinking. Hope crashed the intervention literally by bashing her way into his house with a golf club, furious at having discovered how Bill sabotaged her wedding to Liam. Bill neither admitted nor denied Hope's claims, but was more forthcoming when Liam later demanded answers. Liam washed his hands of Bill, who stabbed himself in the chest with his sword necklace. Liam backed off, but Bill had purposely stabbed himself in his money pouch to further manipulate his son.
Bill was annoyed when Katie got rid of all his alcohol. It was revealed that he and Katie hadn't been making love, so Brooke arranged a night of passion for them, which backfired when Katie smelled whiskey on Bill's breath. Brooke pleaded Katie's case despite the sparks that remained between her and Bill, who thought of Brooke while in bed to Katie.
Bill's frustration escalated when Katie wanted to spend all her time with baby Will. Meanwhile, Brooke fretted over Taylor's increasing influence over Eric, who had begun dating Taylor. Bill encouraged Brooke to counter Taylor by becoming more active at Forrester, starting with rebooting the once successful Brooke's Bedroom lingerie line. Brooke stated she was too old to model lingerie, but Bill bolstered her confidence and talked her into showing off the undergarments she was already wearing.
With Bill's help, Brooke interrupted Thomas' marketing presentation with a mini showing of Brooke's Bedroom. Eric green-lit the project, and Bill celebrated with Brooke, who was still clad in the sexy skivvies. Taylor spotted them, but when Taylor berated Brooke, Bill told Taylor that Brooke would be a role model for women over 40 and that Taylor should get over her obsession with Brooke. At Taylor's urging, Katie interrupted Bill and Brooke's boozy flirting just as they fell onto the bed Forrester used as a prop. Katie blasted Bill, who felt it unnecessary to tell Brooke nothing was going to happen between them and decried what he felt were Katie's "rules and regulations." Bill privately told Brooke he felt like he married the wrong sister.
Later, at home, Bill and Katie tried to come to terms, but when Bill wanted sex from his wife, Katie said she didn't have it to give. Bill drowned his frustration with booze, then swerved into Brooke's car while driving drunk. Brooke hid Bill's car and took him home to recuperate, not wanting Katie to find out. When Brooke called Katie and told her Bill was spending the night without revealing why, Katie marched over and found a shirtless Bill in Brooke's bed. Bill and Brooke explained about the accident, but Katie swore she was done with her marriage to Bill, and took off her wedding ring. Bill and Brooke took this to mean they were free to make love. As they reveled in their afterglow, the hospital called with news that Katie had suffered heart failure.
Brooke blamed herself when she found out Katie hadn't been taking her anti-rejection medication. Bill felt bad for Katie, but reiterated that his marriage was over. Bill responded to Taylor's questions by firing her as Katie's therapist and deriding Taylor's seeming vendetta against Brooke. Katie's first word upon awakening from her coma was "ring," so Brooke insisted Bill put it back on Katie's finger. Bill reluctantly agreed, surprised when Katie apologized for suspecting him and declared that she trusted him implicitly. Bill bought Katie expensive diamond earrings, saying only that he was committed to his family.
Bill was on hand when Liam married Steffy in an unusual ceremony that saw Steffy riding up the aisle on a motorcycle wearing a black dress/suit ensemble. Bill toasted the couple, and Steffy's uniqueness, but Justin half-jokingly remarked to Bill that Liam had finally married Steffy without any undue influence from Bill.
