At age 6, Henrie signed with a SAG agency in Phoenix and began going out on auditions. At age 9, during a regional commercial shoot in Scottsdale, a director recommended that Henrie move to LA. That summer, at the age of 10, he and his family relocated to Hollywood. Henrie booked his first two national commercial auditions, playing silly principal roles in spots for Burger King and Quaker Oats. Henrie booked his first co-starring role on the TV show Providence, and went on to land a guest star role on the premiere episode of Without a Trace.
By age 13, Henrie got his first big break, landing a regular role as Petey Pitt on the Fox sitcom The Pitts. Henrie next landed a leading role in the Hallmark movie, Monster Maker, with Linda Blair and George Kennedy, and was asked to come back for another Hallmark movie, to play a role in Dead Hollywood Mom's Society.
At the age of 18, Henrie got the role of Justin Russo in the Disney Channel Original Series, Wizards of Waverly Place. The show premiered on October 12, 2007. Due to his involvement with Disney Channel, Henrie competed in the 2008 Disney Channel Games. He was team captain of the Green Team, also known as the Cyclones. He has a role in the Disney Channel Original Movie Dadnapped. Before his present role on Wizards of Waverly Place, he had a recurring role on That's So Raven as Cory's friend Larry. Henrie also has a recurring role on How I Met Your Mother, where he plays the lead character's future son.