His theatrical roles include Mr. Tumnus in The Chronicles of Narnia: The Lion, the Witch, and the Wardrobe, Mr. Mayor in Seussical, Carisford in Little Princess, and Phao in The Jungle Book.

Lambert was discovered at an open casting call by agent Joy Pervis in Atlanta.

From 2009 to 2010 Lambert starred as Jason Landers, Charlie Landers/Aaron Stone's brother, in Aaron Stone, and Goose in the Disney Channel original movie Den Brother, also starring Hutch Dano.

Lambert starred in the Hallmark Hall of Fame movie A Smile As Big As The Moon, which aired on January 29, 2012.

[5][6] His mother has stated that his birth year as reported on most websites (1992) is incorrect, and that Lambert was born on November 29, 1993.