Adam Chandler, III, or AJ, is the son of J.R. Chandler and Babe Carey and the grandson of Adam Chandler and David Hayward. However, he was kidnapped at birth by Babe's former husband Paul Cramer and given to Paul's sister in Llanview, Pennsylvania. AJ spent most of the first year of his life being raised by Kelly Cramer and her husband Kevin Buchanan. When AJ was reunited with his biological parents, he became the center of many custodial schemes and battles between his parents. Just when the relationship between his mother and father seemed to be on stable ground, a tornado struck the town and his mother was killed in her attempt to protect her son.

After the death of his mother, AJ's father struggled with his grief. J.R.'s life seemed to turn around when he met Marissa Tasker, Babe's fraternal twin. AJ bonded with his aunt and was overjoyed when J.R. and Marissa were married. Marissa legally adopted AJ but her marriage to J.R. quickly fell apart. After the divorce, Marissa was given full custody of AJ and they moved into a home with Marissa's girlfriend Bianca Montgomery.

Time advanced five years between the final episode on ABC and the first episode of Prospect Park's online version.

A.J. grew into a teenager while his father spent five years in a coma after being shot by A.J.'s grandfather David Hayward. David had sought revenge after J.R. killed David's daughter Marissa. After Marissa's death, her lover Bianca remained in Pine Valley and raised her daughters while A.J. moved back into the Chandler mansion. A.J. and Bianca's oldest daughter Miranda attended high school together and were close friends. Miranda provided A.J. with emotional support after his father unexpectedly emerged from his coma and did not recognize him.

As A.J. tried to figure out how his father fit into his life, his grandfather David was released from prison and also hoped to develop a relationship with him. A.J tried to ignore both men and instead focused on baseball and his friendship with Miranda. She was the victim of several cruel pranks as her peers insinuated that she was gay like her mother. A.J. defended Miranda at his own expense and he seemed to care about her in a romantic way. They shared a kiss but A.J. assumed that Miranda was not interested in him after she encouraged him to date her friend Heather.

When J.R. was released from the hospital, he moved back into the Chandler mansion. A.J. tried to ignore his father but began to soften towards him as J.R. worked to regain his life and his physical strength. At the same time, A.J.'s teammates pressured him to use steroids to improve his athletic performance. He took the steroids home to dispose of but his father discovered them and started to use the steroids himself. A.J. recognized J.R.'s steroid induced rages and dismissed his father from his life. J.R. later apologized and asked A.J. for another chance to develop a relationship but A.J. refused.