Born in Roseau, Minnesota, Garrett spent his early years growing up on a farm in a small town. When he was in the ninth grade his family moved to Scottsdale Arizona, where he began taking private acting lessons. After graduating high school, he immediately moved to Los Angeles to pursue an acting career. One month later, he'd landed the role of Achilles' cousin Patroclus in the major motion picture Troy (2004) opposite Brad Pitt. His next feature was Friday night lights (2004) starring Billy Bob Thornton, in which Garrett played a high school football player. He then landed a starring role opposite Mark Wahlberg in Four Brothers (2005), playing one of four brothers whose mother is murdered.
Troy
(Patroclus)
Eragon
(Murtagh)
TRON: Legacy
(Sam Flynn)
Death Sentence
(Billy Darley)
Four Brothers
(Jack Mercer)
The Absence of Eden
(Shipp)
Friday Night Lights
(Don Billingsley)
Georgia Rule
(Harlan Wilson)
Country Strong
(Beau Hutton)
The Ploughmen
(Val)
Barron's Cove
(Caleb)
TRON: The Next Day
(Sam Flynn)
On the Road
(Dean Moriarty / Neal Cassady)
Inside Llewyn Davis
(Johnny Five)
Visualizing TRON
(Self)
Launching the Legacy
(Self)
Installing the Cast
(Self)
Unbroken
(John Fitzgerald)
Lullaby
(Jonathan)
Pan
(James Hook)
The Tutor
(Ethan Campbell)
Inside 'Inside Llewyn Davis'
(Self)
Mojave
(Thomas)
Desperation Road
(Russell Gaines)
Billy Lynn's Long Halftime Walk
(David Dime)
Mudbound
(Jamie McAllan)
Burden
(Mike Burden)
Triple Frontier
(Ben Miller)
Dreamland
(Perry Montroy)
Party of the Century
Dirt Music
(Luther)
Long Way Back Home
(Corey)
The United States vs. Billie Holiday
(Harry Anslinger)
Violent Talent
The Marsh King's Daughter
(Stephen)
Modern Love
(Spence)
Mosaic
(Joel Hurley)
Lawmen: Bass Reeves
(Garrett Montgomery)
Tulsa King
(Mitch Keller)
Tulsa King
(Self - Mitch Keller)
JonBenét Ramsey
(Steve Thomas)