Foster appeared in the small indie film
The Horrible Flowers, before landing the regular role in the
ABC Family comedy-drama series,
Greek. The series ran from 2007 to 2011. During his days on
Greek, Foster also had the leading role in the independent film,
Teenage Dirtbag. He later guest-starred on
Law & Order: LA,
Melissa & Joey,
Friends with Benefits,
The Closer, and
Parenthood. In 2012, Foster had recurring roles in the fifth season of
Showtime comedy-drama series,
Californication, and short-lived
ABC paranormal horror series,
The River. In 2013, he had the regular role in another short-lived ABC series,
Zero Hour opposite
Anthony Edwards and
Carmen Ejogo. In 2014, Foster had recurring roles in
AMC period drama,
Halt and Catch Fire, and later in that year began appearing in the ABC Family drama series,
Chasing Life as a love interest for the lead character. Also in 2014, he played the role of
Kristoff in the fourth season of ABC fantasy series,
Once Upon a Time. In 2015, Foster began starring in the ABC prime time television soap opera,
Blood & Oil alongside
Don Johnson and
Amber Valletta. In 2015, he was listed one of
Variety’s "10 Actors to Watch". In January 2021, it was announced that Foster had been cast in the recurring role of Ryan Goodwin on the third season of the
Netflix thriller series
You. In 2023, he played the main character's boyfriend Paul in the Netflix interactive romcom film
Choose Love. ==Personal life==