In 2005, Justin Gaston left his hometown of Pineville, Louisiana at age 17 to pursue a career in acting. Gaston first found work as a model for 2(x)ist underwear, Christian Audigier, Adidas, International Jock, Hugo Boss, and other notable labels.
In 2008 Gaston was a guitar player for the Hannah Montana band in the Hannah Montana (season 3) concert. This led to Gaston's nine month dating relationship with the series star, Miley Cyrus.
Gaston appeared as Taylor Swift's love interest on her 2008 music video for "Love Story", and also appeared on the pilot episode of the television series Glee, which premiered on the Fox network on May 19, 2009.
In February of 2010, Gaston began appearing on Simon Fuller's innovative interactive reality show, the If I Can Dream webseries, which aired on Hulu. The show provided round-the-clock coverage of the daily lives of five aspiring stars who had moved into a house in Hollywood, California. Gaston's If I Can Dream (series) costars were: Ben Elliott, Giglianne Braga, Kara Killmer, and Amanda Phillips.
On April 14, 2010, Gaston performed a duet on Simon Fuller's American Idol with Brooke White, the fifth place finalist on American Idol (season 7). Appropriately, Gaston's song choice was the classic Elvis Presley ballad, If I Can Dream.
In June of 2010 Gaston posed nude in a controversial photo shoot for PETA's "Rather Go Naked Than Wear Fur" ad campaign along with If I Can Dream (series) castmates Ben Elliott and Giglianne Braga.