David Lee Gallagher (born February 9, 1985) is an American actor. Beginning a prolific career as a child actor and model at the age of two, Gallagher is a five-time Young Artist Award nominee and Teen Choice Award winner, best known for his role as Simon Camden on the long-running television series 7th Heaven, as well as for his feature film roles; as Mikey Ubriacco in Look Who's Talking Now, as Kevin Harper in Angels in the Endzone and as Richie Rich in Richie Rich's Christmas Wish. Gallagher is also well known for the voice of Riku in the Kingdom Hearts video game series.
Gallagher was born in New York City, New York to Elena Gallagher (née Lopez) and Darren James Gallagher. His parents separated when he was a baby and his mother remarried Vincent Casey. Gallagher is of Cuban descent on his mother's side and Irish descent on his father's side. He has four younger half-siblings, Michelle (b. 1988), Kelly (b. 1991), Kyle (b. 1995) and Killian (b. 1997). Killian was diagnosed with autism and as a result David is an active supporter and spokesman for the organization Cure Autism Now.