Personal life

Gallagher was born in College Point, 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 spokesperson for the organization Cure Autism Now.

He graduated from Chaminade College Preparatory School (California) in 2003 and enrolled at the University of Southern California, where he majored in film and television studies, graduating in May 2007.

Career

Gallagher began acting at the age of 2, first modeling for print advertorials in and around New York City which eventually led to commercial work as an actor. He appeared in many television commercials as a toddler for products such as Tyson Foods and Fisher Price. At age 8 he briefly had a recurring role on the soap opera Loving.

His film debut came in 1993 when he won the role of Mikey in the sequel Look Who's Talking Now, playing the son of John Travolta and Kirstie Alley. In 1995 he played in a production of A Christmas Carol on Broadway. He also starred in several TV movies, including Bermuda Triangle.

In 1996 he reunited with John Travolta for the movie Phenomenon. Later that year, he was cast as Simon Camden in the family drama series 7th Heaven. 7th Heaven remained on the air for 11 seasons, making it the longest-running family drama in television history, and also became the highest-rated show on The WB Network.

He filmed a few movies during hiatuses from filming, including the direct-to-video Richie Rich's Christmas Wish and Little Secrets with Evan Rachel Wood. In 2003, during 7th Heaven 's 8th season, David left the show in order to attend college full-time. However, he returned to the series part-time during season 9 and for what was thought to be the 10th and final season. In late 2006 The CW unexpectedly picked up the show for an 11th season. David opted not to renew his contract.

In 2005 David starred in and co-produced a low-budget adaptation of The Picture of Dorian Gray.

His first role after leaving 7th Heaven was a guest stint on Numb3rs, playing serial killer Buck Winters in September 2006, a role which he reprised in January 2009. He also appeared in the season 6 opener of CSI: Miami, playing another suspected killer. He also starred in the horror sequel Boogeyman 2, which went straight to DVD. In July 2008, Gallagher guest-starred on the TNT drama Saving Grace as Paul Shapiro, a troubled young man who was the suspect in a murder investigation. His next guest appearance was in an October 2008 episode of the FOX crime drama Bones as Ryan Stephenson, the son of a man who later became a woman. Then in November 2008 he appeared in an episode of the CBS show Without a Trace as a suspect named Jeff Ellis who was thought to be responsible for the disappearance of a local nurse. He's also notable for having voiced Riku in the Kingdom Hearts video game franchise and for portraying Seiji Amasawa in the English dub version of Studio Ghibli's Whisper of the Heart. He appeared on the second-to-last episode of the series The Deep End, where he played a man charged with second-degree murder although he is innocent.

In March 2012, David has been announced to star with Jake Weber in Scared of the Dark directed by Takashi Shimizu.

Filmography

Year	Title	Role	Notes
1993	Look Who's Talking Now	Mikey Ubriacco
1995	It Was Him or Us	Stevie Pomeroy	TV movie
1996	Summer of Fear	Zack	TV movie
1996	Bermuda Triangle	Sam	TV movie
1996	Phenomenon	Al Pennamin
1996-2006	7th Heaven	Simon Camden	197 episodes, Season 1-7&10 full-time, Season 8-9 part-time
1997	Angels in the Endzone	Kevin Harper	TV movie
1997	Walker, Texas Ranger	Chad Morgan	Episode: "Brainchild"
1998	Ri¢hie Ri¢h's Christmas Wish	Ri¢hie Ri¢h	Video
1999	Rocket Power	Oliver Van Rossum (voice)	Episode: "Super McVarial 900/Loss of Squid"
1999	Wild Thornberrys, TheThe Wild Thornberrys	Ben (voice)	Episode: "Lost and Foundation" & "Every Little Bit Alps"
2000	New Adventures of Spin and Marty: Suspect Behavior, TheThe New Adventures of Spin and Marty: Suspect Behavior	Marty Markham	TV movie
2001	Little Secrets	David
2003	Kart Racer	Scott McKenna
2005	Quiet, TheThe Quiet	Brian
2006	Whisper of the Heart	Seiji Amasawa (voice)
2006	Sunday Morning		Video
2006-2009	Numb3rs	Buck Winters	Episode: "Spree" Episode: "Two Daughters" Episode: "Arrow of Time"
2007	Picture of Dorian Gray, TheThe Picture of Dorian Gray	Dorian Gray	also co-producer
2007	CSI: Miami	Rick Bates	Episode: "Dangerous Son"
2007	Freakin' Zombies, Man!	Duke	Video short
2007	Boogeyman 2	Mark
2008	Saving Grace	Paul Shapiro	Episode: "A Survivor Lives Here"
2008	Bones	Ryan Stephenson	Episode: "The He in the She"
2008	Without a Trace	Jeff Ellis	Episode: "Push Comes to Shove"
2009	Smallville	Zan	Episode: "Idol"
2010	Betwixt		TV movie
2010	Deep End, TheThe Deep End	Kevin Mather	Episode: "An Innocent Man"
2011	Super 8	Donny
2011	Trophy Kids	Reid Davis
2011	The Vampire Diaries	Ray Sutton	TV series; 2 episodes
2012	Criminal Minds	Matt Moore	Episode: "The Wheels on the Bus"
2012	CSI: Crime Scene Investigation	Adam Kemp	Episode: "Tressed To Kill"
2012	CSI: NY	Marty Bosch	Episode: "Clean Sweep"
2013	Scared of the Dark	Adam	Pre-production
2013	Second Generation Wayans	Jeremy Silverman	TV series
2014	In Your Eyes	Lyle Soames

Video games

Year	Title	Role
2002	Kingdom Hearts	Riku
2004	Kingdom Hearts Chain of Memories	Riku Riku Replica
2005	Kingdom Hearts II	Riku
2007	Kingdom Hearts II Final Mix	Riku
	Kingdom Hearts Re:Chain of Memories	Riku Riku Replica
2009	Kingdom Hearts 358/2 Days	Riku
2010	Kingdom Hearts Birth by Sleep	Riku Young Xehanort (Uncredited)
2011	Kingdom Hearts Re:coded	Data Riku
2012	Kingdom Hearts 3D: Dream Drop Distance	Riku
2013	Kingdom Hearts HD 1.5 Remix	Riku
2014	Kingdom Hearts HD 2.5 Remix	Riku
2016	Kingdom Hearts HD 2.8 Final Chapter Prologue	Riku

[ Source: Wikipedia ]