Thieriot was signed to talent manager Don Gibble after taking his
improvisation class. He modeled for
Gap and appeared in two short films, before being cast in his first feature film role, 2004's adventure film
Catch That Kid. He was subsequently cast in 2005's action comedy film
The Pacifier, portraying one of the family members protected by a
Navy SEAL (
Vin Diesel). He was nominated for the
Young Artist Award for Best Performance in a Feature Film – Supporting Young Actor for his role. Thieriot then appeared in the drama
The Astronaut Farmer (2007) and the film adaptation of
Nancy Drew (2007). In 2008, he played a younger version of
Hayden Christensen's character in
Jumper. That same year, he appeared in
Kit Kittredge: An American Girl, for which he won the
Young Artist Award Best Performance in a Feature Film – Young Ensemble Cast with his co-stars. In 2009, Thieriot co-starred in the erotic thriller
Chloe.
Chloe enjoyed commercial success and became director
Atom Egoyan's biggest ever box office earner. The following year, he played the lead role in
Wes Craven's horror film
My Soul to Take. In 2011, he starred in the independent comedy
The Family Tree and played the lead role in the drama film
Foreverland. Thieriot then co-starred in the
Mark Tonderai–directed psychological horror-thriller
House at the End of the Street (2012). That same year, he starred in the drama film
Disconnect. Also in 2012, Thieriot was cast in a leading role in
Roland Emmerich's drama pilot for ABC,
Dark Horse, but the project was not picked up to series. From 2013 until its ending in 2017, he portrayed Dylan Massett, the half-brother of
Norman Bates, in the critically acclaimed drama series
Bates Motel. He made his directorial debut on the series with the fifth season episode "Hidden". In 2015, he starred in the
History Channel event miniseries
Texas Rising as
Jack Hays, a captain of the
Texas Rangers, and appeared in the remake of the action-thriller film
Point Break. In 2017, Thieriot began starring as Navy SEAL Clay Spenser in the
CBS drama series
SEAL Team until 2022. In 2022, Thieriot began portraying Bode Leone in the CBS drama series
Fire Country, for which he also serves as a producer. ==Personal life==