Dattilo was born in Kankakee, Illinois, subsequently moving to West Palm Beach, Florida after his parent's divorce. At the age of 7, he moved to Los Angeles. At the age of 9, he began taking acting lessons with his sister, Kristin. A short time later, he landed his first acting job in a re-curring role on HBO's Not Necessarily The News.
Dattilo has one brother, Brent, one sister, Kristin, and three half-sisters, Tiffany, Anna, and Tess.
In 1989, Dattilo graduated from Beverly Hills High School. He attended Santa Monica College in Santa Monica and majored in Psychology.
Dattilo was married to Jessica Denay and they have a son, Gabriel (Gabe), who has high-functioning autism. He is actively involved with Autism charities and "raising Autism awareness".
On July 12, 2011, Dattilo married Elizabeth Cameron in Palos Verdes, California.