The show took a look at the lives of two best friends and neighbors since birth, Tucker and Rebecca, and their respective adventures as they travel through the world of eighth grade. The show was produced by Atlantic Films in association with the Disney Channel (Buena Vista International, Inc.). Flash Forward is notable for being the first original series created by Disney Channel.
Tucker "Tuck" James (Ben Foster) is a 13-year-old who has just started eighth grade and sees it as a life-altering event. Tucker faces the travails of a teen's life with his trademark humor and rebounds from the fouls dealt by bullies and the occasional intruding parent by seeking solace in his friendship with Miles. He and Becca have been best friends since they were born and remain committed to each other through thick and thin.
- Tucker (age 5) is played by Marc Donato
Rebecca "Becca" Fisher (Jewel Staite), also 13, is the much-flustered best friend of Tucker and is experiencing the same disillusionment with eighth grade. Her new best friend is Christine, someone who Becca sees as an easier person than Tucker to confide in about the things that are starting to matter (namely boys). Becca also faces ridicule from her bossy and stuck-up sister Ellen and carries a secret crush on the local pizza maker, Gooch.
- Becca (age 5) is played by Jennifer Pisana
Miles (Theodore Borders) is Tucker's new best friend and starts the eighth grade year off as his constant companion. He often acts as the voice of reason in his relationship with Tucker, often bringing Tucker back down to the ground when Tucker allow his flights of fancy to get the better of him.
Christine "Chris" Harrison (Asia Vieira) is Becca's new best friend and often finds herself in the middle of Becca's schemes and troubles. She serves as a source of companionship and most importantly a listener, someone Becca can confide in during their ever-changing world. Christine is the owner of the dubiously named Steve, a female dog.
Horace (Ricky Mabe) is Tucker's long-suffering brother. He is often the butt of Tucker's jokes and pranks, but holds a great deal of respect for his older brother. He is known for capturing all on his video camera, sometimes using the footage to his advantage as blackmail against Tucker. He is very much the typical annoying little brother.
Played by both Rachel Blanchard (ep. 1-4) and Robin Brûlé. Ellen is Becca's domineering, self-centered older sister. She has no real respect for anyone other than herself and (arguably) her boyfriend Ryan. Ellen is often a source of pain and discomfort for her younger sister.