Tried to help Kelly get away with baby Ace
Duke was the result of a teenage fling between his parents, who married once LeeAnn learned she was pregnant and divorced soon after. There was a fierce custody battle over baby Duke and a time during which LeeAnn even claimed that Max Holden was his father, but eventually LeeAnn was able to take her son and move to Texas. Duke was raised primarily by his mother, with his father an infrequent visitor in their lives, which helped contribute to a rift between Kevin and Duke, with Duke always feeling like he was never first place in Kevin's heart.
Duke arrived in Llanview to attend business school, and was soon embroiled in another bitter custody battle over one of Kevin's children, this time his younger half-brother, Ace. He sided with Kelly during the hearing, even testifying on her behalf, which further widened the rift between Kevin and Duke. The battle over the baby took another turn when Kelly decided to return Ace to his real mother, who had thought the baby died at birth. Duke and Kevin were again at a crossroads, although Duke did testify for Kevin at the second custody battle. When Kevin and Kelly chose to return the baby to his biological mother, Duke stood by his father, and the two began tentatively repairing their relationship.
Throughout the custody battle, Duke's greatest support was from Adriana Cramer. Duke had been intrigued with Adriana the moment they met, even though their families were at war. The two refused to allow their families to tear them apart, and remained a couple despite Adriana's mother Dorian's hatred of all things Buchanan. Kevin and Duke were also trying to forge a relationship again. Duke flirted briefly with Ginger Foley, but it was ultimately Adriana's growing feelings for Rex that led her to break things off.
Duke was devastated and began drinking. He soon revealed that he was in love with his former stepmother, Kelly. Kelly tried to convince him that he didn't really feel the way he thought he did, and she was successful in keeping him away until the day that Michael and Marcie married. Duke found Kelly alone in the rectory, devastated after a horrible argument with Kevin. Circumstances took over, and the two made love. When the tornado hit Llanview, both Kelly and Duke were severely injured. Kevin was forced to choose which of the two would get a life-saving surgery, and he chose Kelly, believing that Duke was stronger.
Duke never made it into surgery and died despite the hospital's best efforts. A few weeks after his death, Kelly learned that she was pregnant with his child.