O'Donnell appeared in numerous commercials as a teenager, advertising
Cap'n Crunch cereal and
Fruit Roll-Ups snacks. In a
McDonald's fast food commercial, he served
NBA great
Michael Jordan. An early television series role was an appearance on the TV series
Jack and Mike in 1986. In the early 1990s, he appeared in several films including ''
Men Don't Leave (1990), starring Jessica Lange; Fried Green Tomatoes (1991), appearing again with Kathy Bates from Men Don't Leave
; School Ties (1992); and Scent of a Woman (1992) with Al Pacino. For the latter he received two nominations: one for a Golden Globe Award for Best Supporting Actor-Motion Picture (which was won by Gene Hackman for Unforgiven''), and one for a
Chicago Film Critics Association Award for Most Promising Actor (which he won). He was also named one of the 12 Promising New Actors of 1992 in John Willis's
Screen World, Vol. 44. After appearing in the film
Blue Sky (1994), reuniting him with Jessica Lange, he starred in
Circle of Friends (1995) with
Minnie Driver,
Mad Love (1995) with
Drew Barrymore, and
In Love and War (1996) with
Sandra Bullock. O'Donnell played the character of Dick Grayson/Robin in
Batman Forever, in which Barrymore also had a role. Reportedly, the field of candidates for the role of Robin included
Leonardo DiCaprio,
Matt Damon,
Jude Law,
Ewan McGregor,
Corey Haim,
Toby Stephens, and
Scott Speedman. Casting directors narrowed their choices to O'Donnell and DiCaprio, and finally selected O'Donnell. He reportedly was considered by
20th Century Fox studios to play the lead role of Jack Dawson in
Titanic (1997), but that role was won by DiCaprio. O'Donnell had a starring role in 1996's
The Chamber, based on the
John Grisham novel of the same name. He reprised his role as Robin in 1997's
Batman & Robin. O'Donnell later said that he did not believe it turned out well. O'Donnell did not appear in another movie for two years. He was the choice of one of the producers for the role of James Darrell Edwards III/Agent J in
Men in Black (1997), but he turned it down as being too similar to his role in
Batman Forever.
Will Smith played this role. The subsequent films ''
Cookie's Fortune (1999) and The Bachelor (1999) were moderately successful, while Vertical Limit'' (2000) was a box office hit. After a four-year hiatus, O'Donnell returned in 2004 with the film
Kinsey. O'Donnell took a lead role in the
Fox Network television series
Head Cases in 2005. The show was the first of the fall 2005 season to be canceled, and only two episodes were aired. He was subsequently cast as
veterinarian Finn Dandridge on the
ABC medical drama ''
Grey's Anatomy''. filming
NCIS, 2009 O'Donnell was featured in the
TNT miniseries
The Company as
CIA case officer Jack McAuliffe, a character who progressed from being a spoonfed
Yale elitist to jaded, post-
Cold War cynic. In 2008, he appeared in
Kit Kittredge: An American Girl as
the titular character's father Jack Kittredge, and in
Max Payne as Jason Colvin. From 2009 to 2023, O'Donnell starred on
NCIS: Los Angeles, a spin-off of
NCIS, as
G. Callen, an NCIS Special Agent in Charge of the Office of Special Projects Team stationed in
Los Angeles.
CBS calls Callen "a chameleon who transforms himself into whomever he needs to be to infiltrate the criminal underworld." In 2010, O'Donnell appeared in the sequel to the 2001 movie
Cats & Dogs,
The Revenge of Kitty Galore. During an appearance on
Live with Kelly and Mark on October 7, 2025 he talked about the
Batman Forever props he has (costumes including outfits, one of which is from the circus aerialist scene). He has his motorcycle helmet from the film. Referring to another prop of his, a costume from
The Three Musketeers, he said "even my dad wore it for
Halloween one year." ==Personal life==