The eldest son of the Grayson family. Formerly a party boy – until a drunk driving accident left a young woman paralyzed – Daniel is a student at Harvard, and later business partner of Conrad. He falls in love with Emily and eventually asks her to marry him. At their engagement party, he is charged with the murder of Tyler Barrol but is eventually exonerated. After Conrad tells Daniel the real story of David Clarke, Daniel chooses to stand by his father and take over the company, rather than expose the truth or separate his way. During season 1, Daniel is thrice lead to accuses Emily of cheating on him with Jack Porter. On the third occasion, which occurs at the season finale, Emily – who is disgusted by Daniel's choice of standing by his father – terminates the engagement.

In Season 2, Daniel is in a relationship with Ashley Davenport and is slowly distancing himself from his father. He succeeds in taking Conrad's position at Grayson Global, unaware of the existence of the Initiative or the threat it presents. Upon discovering Ashley in a hotel room with an investor, he breaks up with her, threatening the businessman with blackmail. He gradually falls for Emily again, and resents Aiden's close relationship with the socialite. Daniel fires Aiden when it is revealed that his father was the one who put the bomb on flight 197. Daniel is the only one Charlotte confides in about her pregnancy.

By season 3 Daniel continues his romance with Emily and plans their wedding. However, problems arise during the beginning of the season between him and Emily, including the untimely arrival of Sara, the girl who he had paralyzed in a car accident. Daniel and Emily marry in episode 10 of season 3. He overhears Emily and Victoria talking about how Emily faked her pregnancy; angered, he shoots Emily, although she survives. Subsequently, they get divorced.