Hoechlin was born and raised in Southern California and began acting at the age of 9. He trained at the Young Actors Space, the Krys Kyer Workshop, and with Warner Laughlin. He won his first film role in Family Tree, which screened at the 1999 Cannes Film Festival, and starred Robert Foster and Naomi Judd. In 2001, Hoechlin starred in the independent film Train Quest, which was shot in Romania.

In 2002, he was chosen from over 2,000 young actors across the country for the coveted role of Tom Hanks' son in Sam Mendes' Road to Perdition. For his critically acclaimed performance in Road to Perdition, Tyler was nominated for a Broadcast Film Critics Award for Best Young Actor, and was awarded the Best Young Leading Actor prize by the Young Artists Foundation. In addition, The Academy of Science Fiction, Fantasy and Horror Films awarded Tyler the prestigious Saturn Award for his turn in the film.

Tyler was nominated for a 2004 Teen Choice Award for Breakout Male Star.

Besides acting, Hoechlin is a standout baseball talent. He began playing at the age of seven and represented his country as a member of the U.S. team in the Pan American games when he was only 9.