James Kenyon III -- Trey (as in slang for the number three -- showed up at the door to Greenlee Smythe's penthouse hoping to get a look at a apartment she had for rent. Greenlee had bought a loft in her building in an attempt to give Simone Torres the boot. Things backfired and Simone got to stay -- but she needed a roommate. Trey answered the ad and mistook Greenlee for a landlady. Trey was obviously taken with Greenlee and shamelessly flirted with her.
When Trey showed up in Vanessa Cortlandt's room, he revealed that he was the son of a lawyer slated to represent Vanessa in court. Apparently his dad was busy and unable to help her out. On top of that, he was worried that Vanessa's case would sully his reputation.
As spring and summer 2002 passed, Trey secretly worked to uncover Vanessa's drug money from her days as Proteus drug lord. Leo and Greenlee, who had never fully trusted him to begin with, began working to find out Trey's motives. Leo discovered that Trey Kenyon had died several years earlier in a boating accident, and the man they knew was Trey's best friend, Ben Shepherd. Meanwhile, Trey revealed to Vanessa that he was the long-lost son she had given up at birth, and had been shuffled from foster home to foster home, neglected and abused by the rare temporary parents he did have. Vanessa, then under the influence of sweet alternate personality Nessa, welcomed her son with open arms and encouraged David and Leo to accept him. Leo and Trey were very wary of being anything other than adversaries, but worked together to find the Proteus holdings. When they realized the holdings were nothing more than worthless stocks, they collapsed in laughter and had their first bonding moment. Thereafter Leo was fiercely loyal to his brother and forgave him for all of his past crimes against Leo, Greenlee, and others. Around the same time, Kendall and Trey found out that Trey's father was Richard Fields, from an affair of Vanessa's during her Hollywood years. Although she was outraged when he confessed to her that he had set the fire in Erica's home and framed her for the crime, she also forgave her newfound half-brother. In late October 2002, Vanessa kidnapped Greenlee and Leo and Trey raced off to rescue her. In spite of his lifelong vertigo, Trey climbed to the top of the cliffs in order to save Greenlee's life. As he did so, Leo and Vanessa fell into the falls and were presumed dead.
Devastated, Trey tried to live his life the way Leo would have wanted him to, and helped Greenlee through her painful mourning period. But her constant abuse of him and rejection after he spontaneously kissed her led him to another direction. David asked Trey to represent Reggie, a young street kid who had held David's wife Anna hostage at a free clinic and was about to go to juvenile hall. Over the objections of Janelle Anderson, who ran the clinic and was close to Reggie, Trey became his guardian and worked valiantly to turn Reggie's troubled circumstances around. He even began to have romantic feelings for Janelle. But Trey's brief sense of happiness was eradicated when Reggie began to be menaced by Luis, his old gang boss. Reggie committed various crimes for him, and in his attempts to make Reggie see the error of his ways, Trey confided his arson in Reggie. Soon after, Reggie was dragged into DA Jack Montgomery's office, and knowing that Luis would kill Janelle if Reggie gave him up, he instead ratted out Trey. Trey was bewildered, but in exchange for a reduced sentence and Jack becoming Reggie's guardian, Trey agreed to 3-5 years in state prison. After a brief goodbye to Reggie and Janelle, he was gone.