Johnny Mark Galecki (born April 30, 1975) is an American actor. He is best known for his roles as David Healy in the sitcom Roseanne, and as Leonard Hofstadter, Ph.D in the CBS sitcom The Big Bang Theory.
Galecki was born in Bree, Belgium to American parents. His mother, Mary Lou, is a mortgage consultant, and his father, Richard Galecki, was a member of the U.S. Air Force stationed in Belgium and also worked as a rehabilitation teacher. Galecki moved to Oak Park, Illinois with his family when he was three years old.
His best known role was as David Healy (first introduced as Kevin Healy) in the U.S. sitcom Roseanne. His character was the artistically-talented, curly-haired, soft-spoken boyfriend (later husband) of Darlene, the droll, tomboyish second daughter of the Conner family played by Sara Gilbert. Galecki was cast in similar roles in the 1997 summer slasher, I Know What You Did Last Summer as a jealous loser who has an eye for Jennifer Love Hewitt, and the 1998 dark comedy The Opposite of Sex as a gay teen who lies about being molested. In 1989, he played Russell "Rusty" Griswold in National Lampoon's Christmas Vacation. In the year 2000, Galecki took a bit of a twist and reunited with the same filmmaker, who cast him in Bounce as Seth (a gay man), an assistant to Ben Affleck's character Buddy Amaral, who also helps dodge out with his love life.
Galecki continued his film streak with other David Healy-like roles in Suicide Kings as a nebbishy rich kid who folds easily under pressure, and brief bit parts in high-profile films like Bean as a bad-boyfriend biker, and a minor supporting part in Vanilla Sky. Galecki showed that he had range as an actor with typecast-breaking roles like a young criminal delinquent in A Family Torn Apart, a TV movie based on a true story about a serial murderer and the death of a pair of parents.
He also played the half-brother of the main characters, sisters Hope Shanowski and Faith Fairfield, in the TV Sitcom Hope & Faith. Galecki also appeared as a guest star in a first season episode of My Name Is Earl in which he played a golfer who both Earl and Randy trick into thinking he is an amazing golfer, which subsequently destroys his life as he loses his job and girlfriend. He also played a character named "Trouty" on TBS's sitcom, My Boys.
Galecki starred fall/winter 2006-07 in the Broadway play The Little Dog Laughed as Alex, a male prostitute. In this role, he was required to do a full-frontal nude scene, the first of his acting career. Galecki originated the role earlier in 2006 at Second Stage Theatre. The widely popular comedy by Douglas Carter Beane had a successful run at Second Stage and moved to the Cort Theatre. The play closed on February 18, 2007.
Galecki currently stars as Leonard Hofstadter, PhD on a new CBS show, The Big Bang Theory, which debuted September 24, 2007. He also appears in the music video for the Dave Matthews Band song "Satellite".
He plays the cello and has played it while in different characters.
Galecki appeared in the 2008 superhero comedy Hancock, alongside Will Smith and Jason Bateman.
