Christopher Eugene O'Donnell (born June 26, 1970) is an American actor. He played Charlie Sims in Scent of a Woman, Chris Reece in School Ties, D'Artagnan in The Three Musketeers, Jack Foley in the drama film Circle of Friends, Dick Grayson/Robin in Batman Forever and Batman & Robin, Jason Brown in Robert Altman's Cookie's Fortune, Peter Garrett in Vertical Limit, and Wardell Pomeroy in Kinsey. O'Donnell starred as Special Agent G. Callen on the CBS crime drama television series NCIS: Los Angeles, a spin-off of NCIS.

Early life
O'Donnell was born in the Chicago suburb of Winnetka, Illinois, the son of William Charles O'Donnell Sr., a general manager of WBBM-AM, and Julie Ann Rohs von Brecht. He is the youngest of seven children, with four sisters and two brothers, and is of German and Irish descent. O'Donnell was raised in a Catholic family and attended Catholic schools. He graduated from Loyola Academy in Wilmette, Illinois in 1988. O'Donnell then attended Boston College and graduated with a Bachelor of Science in marketing in 1992.

O'Donnell began modeling at the age of 13.