Fancast reports that the actor will play criminal defence attorney Roland Carson in the fifth episode.
The character will encounter Mac (Gary Sinise) and his team after a gang of thieves stage a violent hiest at his Manhattan penthouse.
Harrison is known for his role as 'Gonzo' Gates on CBS medical drama Trapper John, M.D., which ran from 1979 to 1986. More recently he has played Paul Norris, the father of Julian (Austin Nichols), on One Tree Hill.
The new season of CSI: NY begins September 24 on CBS.