Zachar was born in Chicago, Illinois (his Greek character, Rusty Cartwright, is also from Chicago). He attended St. Francis Borgia elementary school. He also attended St. Patrick High School, an all-boysCatholic school in Chicago. Zachar booked his first starring role after living in Los Angeles for only two months. He played the part of Ernest in the film Little Big Top and then appeared as a cashier in the movie Bodega, also in 2006. He has also done commercials for Carl's Jr. and Dunkin' Donuts. He has performed in various theater roles such as On Golden Pond, Prairie Lights, Big: The Musical, Les Misérables and Guys and Dolls. His most recent television role on the show Greek has been going strong for 3 years.
Zachar provided voices for the movie Surf's Up and an episode of the animated television series King of the Hill where he was a cashier. Zachar stars along with Dana Delany, John Malkovich and John Goodman in Drunkboat (2010).