Caan, 33, will step into the role originated by James MacArthur and made famous by the original series' catch phrase, "Book 'em, Danno!"
In the project, Williams is a recent transfer from the Baltimore Police Department who moves to Hawaii after an ugly divorce to be close to his daughter. He partners with Steve McGarrett (Alex O'Loughlin), the head of a special division of the Hawaii State Police. Besides O'Loughlin, Caan joins familiar faces such as Daniel Dae Kim, Grace Park and Taryn Manning.
Caan most recently appeared in a recurring role on the last season of Entourage, playing Eric's competitive co-worker at a Hollywood management firm. Caan, the son of James Caan, will be credited as a guest star in the Hawaii pilot because of his previous commitment to the HBO comedy, THR reported. (MacArthur also was the son of show business parents — playwright Charles MacArthur and stage legend Helen Hayes.)
Caan is also best known for his role in all three Ocean's films.