Lucas was born to Cheryl Stansbury and presumed deceased mobster Julian Jerome but Cheryl had been told that her baby had died. In truth, Lucas was sold to Bobbie Spencer Jones, who was desperate to adopt a child after her planned legal adoption fell through at the last minute. Bobbie named the baby Lucas after her brother, Luke Spencer. She was unaware that Lucas was Cheryl's child.
In 1990, baby Lucas fell ill and was diagnosed with juvenile diabetes. Bobbie decided to investigate Lucas's biological family and turned up proof that Lucas was Cheryl's son. Bobbie kept the information to herself but Robert Scorpio learned the truth and planned to reunite Cheryl with her child. Bobbie tried to flee with Lucas but Robert stopped her. Tony was distraught over Bobbie's lies and took his daughter B.J. and left Bobbie. They later reconciled.
Lucas lived with his biological mother until she was killed in a car accident. Cheryl's will stated that he be raised by Tony and Bobbie but Cheryl's sister Tiffany Hill sought custody as well and a legal battle ensued. In the end, Bobbie and Tony were granted custody and Lucas referred to them as his parents.
As part of the Jones family, Lucas was devastated when his cousin Maxie was diagnosed with heart disease and required a heart transplant. Shortly after the diagnosis, Lucas's sister B.J. was rendered brain-dead in a school bus accident. Tony made the difficult decision to donate B.J.'s heart to Maxie, and Tony and Bobbie explained to Lucas that B.J. was going to live in Heaven. After B.J.'s death, his parents struggled to make their marriage work and Lucas eventually came to terms with their decision to divorce.
A few years later, Lucas became deathly ill after Helena Cassadine poisoned him with a deadly bio-toxin. Helena offered the cure to Tony in exchange for his assistance reviving her son Stavros Cassadine from his frozen state. Tony acquired the cure for Lucas and he made a full recovery while Luke shut down Helena's operations.
In 2002, Lucas was doing poorly in school. He confessed to Maxie and Georgie Jones that he had trouble concentrating when he tried to study. Georgie determined that Lucas had a learning disability. While working overtime to help Lucas with his studies, Georgie developed a crush on him. Unfortunately for Georgie, Lucas had developed a crush of his own on Maxie. Even though Maxie did not return his feelings, Lucas stood by her and helped restore her damaged reputation. Eventually Lucas decided to give his attention to Georgie but was concerned over her growing friendship with Dillon Quartermaine.
Lucas left town to attend boarding school and when he returned, he learned that Dillon and Georgie were a couple. Lucas met Brook Lynn Ashton and he appreciated her uniqueness and they grew closer as they helped Georgie and Dillon navigate their relationship. Brook Lynn and Lucas shared a kiss but their relationship never moved beyond friendship.
Later, Lucas revealed to his family and friends that he was gay. Bobbie struggled with the news whereas Tony gave his full support to his son. A few months later Tony died unexpectedly from an epidemic outbreak and Lucas mourned the loss of his father. After his father's death, Lucas moved to Seattle and Bobbie moved there as well a few years later.
Lucas returned to Port Charles to be with his mother after Carly went missing. He ran into his other sister Sam Morgan and his biological father Julian Jerome. Lucas was shocked to discover that Julian was alive and wondered why his mother had not told him. As Lucas digested the news, he met General Hospital lab technician Brad Cooper and Brad shared that though he had been raised by adoptive parents, his biological father was the former organized crime figure Kim Wu. Lucas was surprised by how much he and Brad had in common and they spent the night together. The next day, Lucas let Brad know that he was interested in pursuing what they might have despite Brad's attraction to a man named Felix.
When Brad's relationship with Felix failed to progress, Lucas and Brad decided to date. However, Lucas quickly ended his involvement with Brad after he learned his new beau had helped Britt Westbourne and her mother keep Lulu away from her biological son. Brad begged Lucas for another chance but Lucas refused to associate with someone that had caused his cousin so much pain. Felix was also disappointed in Brad's actions and Lucas and Felix bonded over their connection to Brad.
Lucas took Felix as his date to a family dinner hosted by his father Julian. At the gathering, Julian announced that he had left the mob and vowed to only participate in legitimate business. Shortly after the declaration, a man entered and shot Lucas in the chest. He was rushed to the hospital and underwent surgery while his family prayed that he would survive. When Lucas was released from the hospital, both Felix and Brad made their romantic intentions toward Lucas known as he recovered. Lucas eventually chose Brad.