Charleston was born in Paddington, New South Wales, Australia. The middle of five children to Australian-born parents Trevor Charleston, a sports complex manager, and Gail Shoemaker an OBGYN nurse. His mother remarried Robert Shoemaker and moved Kaine to Anaheim, California at age 4. Charleston attended Betsy Ross G.A.T.E. (Gifted And Talented Education) elementary school in Anaheim before the family relocated to Hawaii in order to be half way to Australia and the United States. While living in Australia for primary school, Kaine attended Kai Ora Public School outside Gympie, Queensland. Living with his father in Australia half the year and then his mother in Hawaii the remaining portion, Kaine attended Christian Liberty Academy outside Hilo, Hawaii.
In high school, Charleston left the private school system and attended Hilo High School where he played only Varsity sports his four years (Baseball, Football, Soccer, Track, and Cross Country). He was selected first team all-state in Baseball, Football and Soccer his senior year. Opting to reject a professional baseball contract, Charleston played baseball at Saddleback College for two years until he was plagued with two major injuries, a broken back and a reconstructed wrist. Kaine decided to focus on school and now volunteers with youth leagues worldwide.
Charleston's introduction to acting was by accident, as he had to take an acting class as part of the requirements for his college degree. He became interested in the craft and used a thousand dollars given by his family to shoot a feature film in his hometown of Hilo. Called Hawaiian Summer, the film honors Kaine's two close friends, Sheldon and Kailani, who died while he was in high school.
Kaine impressed Academy Award winning director Ron Howard and landed the role of the Sydney News Director, in Universal's Best Picture Nominated film Frost/Nixon.
Kaine played Det. Fisk on the Showtime series Dexter alongside James Remar, whom he worked with on the movie Sharpshooter starring Mario Van Peebles.
While working on preproduction for the film We Are Marshall, Charleston was offered a small part on the football team by the films' producers Mary Viola and Basil Iwanyk.
On stage, Charleston had parts in high school plays while still in Jr. high school. It wasn't until college he began to stage act under the close teaching of former University of Southern California theater Dean, Ron Elisson.
Kaine has been seen in episodes of the Fox hit show House and Without a Trace, and a co-starring part on The Tonight Show with Jay Leno.
He also had two starring roles on TLC's Untold Stories of the ER. In the 2006 season premiere episode, Kaine co-starred as paramedic search and rescue officer "Brad" and then in the season finale episode Kaine starred as Aussie golfer "Alex".
Plays the arresting officer of Jennifer Nettles in the new Sugarland music video "Stuck Like Glue."
A native of Sydney, Kaine continues to split time between the United States and Australia. While in Los Angeles working, Kaine retreats to San Diego to be with family most weekends. Charleston is an Airstream and old car fanatic. He owns a custom Airstream travel trailer from the 1960s and a 1958 Corvette passed down from his father. Never married, no children, Kaine has a Shepard/Lab mix named "Latte". After the loss of his grandfather Ken Bennett to Alzheimer's Disease, Charleston has become an advocate for the Alzheimer's Association worldwide. In 2002, Charleston joined with longtime friend Kim Lacroix to form a production company, Aussie Boy Films, whose first project was Hawaiian Summer in 2004. Now a part of Bleu Bubble Productions, the joined companies write, develop and edit feature films, documentary films, short films, and music videos.