Lucas Prentiss was the son of Vanessa Prentiss and younger brother to Lance Prentiss, the wealthy family that owned Prentiss Industries. Lance and Vanessa lived in an estate not far from Genoa City on Lake Geneva. Lucas lived in Hong Kong since shortly after he had accidentally caused a fire in which his mother received serious facial burns while rescuing Lance. Once Lucas had found out that his mother would survive, he had disappeared because he felt guilty for causing the fire and her disfigurement.
Several years later, Lance was intrigued by Genoa City concert pianist, Leslie Brooks, but because Leslie was married to Brad Eliot, the two were just friends. Leslie would often spot Lance in the audience as she toured the world performing, and he would meet her afterward for dinner.
Leslie set Lance up with her younger sister, Lorie, who unlike the sedate and serious Leslie, was a headstrong novelist. After being lavishly romanced by Lance, Lorie gave in to his charms. Lorie, however, was confused by Lance's estate. There were locked rooms that Lorie had never seen, and she never understood why she kept finding scarves monogrammed with the initial "V."
Eventually when things began to get serious between them, Lance explained that his mother Vanessa lived at the estate, and was a recluse who wore a veil over the lower part of her face to hide the scars incurred years ago when she had rescued Lance from a fire which had been accidentally started by his younger brother Lucas. Vanessa had been peering through peepholes in the walls of the mansion for years, and had observed Lance with Lorie and other women before her, including her sister Leslie.
Vanessa was displeased by Lance's involvement with Lorie, whom she viewed as a potential threat to her having her son all to herself. Lance and Lorie were married on the spur of the moment during a trip to Lake Tahoe, and Lorie moved in with Lance and Vanessa. Although Vanessa was always gracious in front of Lance, she was spiteful to Lorie when he was not around. Not easily dissuaded, Lorie attempted to build a relationship with Vanessa and even suggested that Vanessa have plastic surgery to remove her scars. But Vanessa told her that her heart condition had made plastic surgery too risky. Later during one of their many altercations, Lorie told Vanessa that she had learned that Vanessa had no heart condition and accused her not being scarred at all. To which Vanessa lifted her veil and revealed her horribly scarred face. Lorie then accused her of only refusing plastic surgery to hang onto Lance. Vanessa threatened Lorie, if that accusation ever got back to Lance.
Lorie tracked down Lance's brother, Lucas, in Hong Kong and persuaded him to return home, hoping the diversion would stop Vanessa's obsession with Lance. Vanessa welcomed Lucas home with open arms and gratitude to Lorie. Vanessa assured Lucas that she had never held him responsible, and he was able to convince her to finally have the plastic surgery that removed her scars.
Leslie, while on a concert tour, found out that Lorie had written a book about their sibling rivalry and Leslie's nervous breakdown. Finding herself hounded by reporters anxiously seeking the tawdry details about her time spent in a sanitarium, Leslie became so upset that she nearly suffered a second breakdown. When Lance heard what his wife had done, he flew to Denver to meet Leslie to give her emotional support. But when Leslie surveyed the audience, imagining them all knowing about her past, she froze, and then ran off the stage. Lance comforted Leslie, and they returned to her hotel suite, where they ended up making love.
Leslie discovered that she was pregnant, but just as she was about to tell Lance that he was going to be a father, Lance told her that he was going to reconcile with Lori. Reeling from Lance's decision, Leslie went on to her next concert date in Seattle. Lucas followed, who by then had fallen in love with Leslie. After Leslie confessed that she was carrying Lance's child, Lucas sympathized and proposed. Leslie and Lucas declared that they would never tell Lance that the baby was his, and they were married. Leslie's mentor, Maestro Fautsch, let them live in his villa in Switzerland to keep the baby's birth date a secret. Leslie gave birth to a healthy baby boy, whom she named Brooks Lucas Prentiss.
Meanwhile, Vanessa, as part of her latest scheme to break up Lance and Lorie, invited Lucas to join Prentiss Industries. Once her baby had been born, Leslie offered Lucas his freedom, but Lucas wanted to stay married to her. They returned to Genoa City, and Lucas went to work with his mother. Vanessa had been transferring stock into Lucas' name until they were able to remove Lance as president, and Lucas took his place. Lucas felt guilty, and offered Lance the position of heading the European office in Paris. Lance refused, and he and Lorie moved from the estate to a penthouse in Genoa City. Before they left, Vanessa confided to Lorie that the only way Lance would be reinstated was if Lorie divorced him.
Lucas went to join Leslie and Brooks on her concert stop in Australia. But Lance was already there visiting Leslie. Lucas spotted them together having dinner, and assumed they were in love. But Lance had actually been telling Leslie that he intended to commit to Lorie and accept Lucas' job offer in Paris. So when Lance later accepted the Paris job, Lucas rescinded it and offered him a job heading up their dangerous Santa Domingo office instead.
Although Leslie appreciated the support that Lucas gave her, she realized that she didn't really love him, and they divorced. Lance convinced Leslie and Brooks to live at the penthouse with him and Lorie. But after an upsetting confrontation with Lorie, who correctly guessed that Lance was really Brooks' father, Leslie suffered another nervous breakdown and disappeared, leaving Brooks behind.
Wandering aimlessly with amnesia in another town, Leslie found herself at a bar. Jonas, the owner, was immediately drawn to Leslie, who told him that her name was Priscilla. Jonas turned her from a brunette to a blonde and she began playing the piano and singing at his club. Leslie became so happy and in love with Jonas that she no longer cared about discovering her past. But when her doctor told her that she had had a baby not that long ago, Jonas became worried that there was a child growing up somewhere without a mother.
As Lance became more and more depressed without his work, Lorie decided to get him to divorce her so that Vanessa would let him come back to Prentiss Industries. Lance and Lorie ended up divorced, and Vanessa gave Lance the European division office to run from Paris.
Meanwhile, Lucas had turned to Dr. Casey Reed who was trying to get over her love for Dr. Snapper Foster whose estranged wife, Chris, had returned and wanted him back. After drowning their sorrows together in bar, they ended up in bed together.
Lucas and Jonas met when both went off to fight the dictator of San Leandro. Lucas discovered "Pricilla" as a stowaway on the jet, but Leslie didn’t recognize him, and it was obvious that she was in love with Jonas. After their successful adventure, they all returned to Genoa City. "Pricilla" met Lorie, but did not recognize her either. Lorie and Lucas told Leslie who she was and who they were, but Leslie became confused and overwhelmed. Lorie worried that Leslie would soon regain her memory and demand custody of Brooks. But Leslie explained that she couldn't be a proper mother to a child she did not remember, and she gave full custody of Brooks to Lorie. As Leslie and Jonas were about to leave the Allegro for home, Leslie encountered Maestro Fautsch who persuaded her to play for him. Leslie was amazed as classical music flowed from her fingertips. When she realized how truly gifted she was, she decided to stay in Genoa City, and she persuaded Jonas to stay as well, and to take over her club, The Allegro, which he renamed Jonas's.
Lucas became jealous of Jonas, and determined to win Leslie away from him, Lucas convinced Leslie to go on a cruise with him. Casey and Jonas commiserated together and became close friends. But Leslie was unable to make love with Lucas, and their reconciliation was short-lived. Lucas and Lorie then became lovers, and Lucas finally asked her to marry him. But Lorie knew she had just been using him and still loved Lance, so she turned Lucas down.
After falling and hitting her head, Leslie regained her memory and recalled her love for Lance and that he was the father of her son. Leslie filed for custody of Brooks, but lost him to Lorie because she was the only mother he had ever known.
After his mother, Vanessa, committed suicide and Victor Newman took over Prentiss Industries, Lucas left town for parts unknown.