Johnny Galecki

John Mark Galecki (born April 30, 1975) is an American actor. In television, he played Leonard Hofstadter on The Big Bang Theory (2007–2019) and David Healy in Roseanne (1992–1997; 2018) and The Conners (2018–2019). Galecki also appeared in the films Prancer (1989), National Lampoon's Christmas Vacation (1989), Suicide Kings (1997), I Know What You Did Last Summer (1997), Bookies (2003), In Time (2011), and Rings (2017).

He was one of the highest paid television actors in the world, with his role in The Big Bang Theory earning him approximately US$900,000 per episode between 2017 and 2019. In 2018, Galecki was estimated to be the world's second highest-paid male TV actor by Forbes—behind only his The Big Bang Theory co-star Jim Parsons—earning $25 million. The accolades he has received include a Satellite Award, alongside nominations for a Primetime Emmy Award, Golden Globe Award, and six Screen Actors Guild Awards.

Galecki was born in Bree, Limburg, Belgium, to American parents of Polish, Irish, and Italian descent. His mother, Mary Louise "Mary Lou" Noon, was a mortgage consultant, and his father, Richard Galecki, was a member of the U.S. Air Force stationed in Belgium and worked as a rehabilitation teacher. Galecki is the eldest of three children with a sister, Allison, and a brother, Nick, who he describes as a "mechanical genius" in the automotive industry. Galecki grew up in Oak Park, Illinois. He dropped out of school after 8th grade, attending high school for only one day.

During an interview with New Zealand radio station ZM, Galecki recalled his childhood relationship with his mother. As a child, he was well known for making up long stories and tales. In such situations, his mother used to make him play the "quiet game", where he had to see how long he could go without talking. He also recalled that despite being a loving mother, she was also very tough. One phrase she would lovingly use was, "I love you, now get out."

After working in the Chicago theatre scene as a young child, Galecki made his onscreen acting debut in the 1987 CBS miniseries Murder Ordained with JoBeth Williams and future Roseanne co-star John Goodman. In 1989, Galecki portrayed Rusty Griswold in National Lampoon's Christmas Vacation. In 1990, he was cast as Danny Nash, the son of Robert Urich's lead character, on the NBC comedy American Dreamer; the following season, he was a regular cast member on the ABC sitcom Billy, a spin-off from Head of the Class. He appeared in one episode of Blossom in 1991, opposite his future The Big Bang Theory co-star Mayim Bialik. He played a young delinquent in A Family Torn Apart, a 1993 TV movie based on a true story about a serial killer.

During his run on Billy, Galecki began making guest appearances on the hit ABC sitcom Roseanne as the younger brother of Mark Healy (Glenn Quinn), who began a relationship with Darlene Conner (Sara Gilbert). Introduced in his first appearance as Kevin Healy, his name was soon changed to David. After a few more guest shots, Galecki was named a permanent Roseanne cast member from the fall of 1992 onward, after the cancellation of Billy. He would remain in the role of David Healy until the end of Roseanne's run in 1997, with the character eventually marrying Darlene and fathering two children with her. Galecki's character on The Big Bang Theory would also have a short-lived relationship with Gilbert's character on the same show.

Galecki also appeared in the 1995 music video for the Dave Matthews Band song "Satellite".

After Roseanne ended, Galecki had small roles in a string of films, including the 1997 summer slasher film I Know What You Did Last Summer (as the killer's first victim), Bean (1997), The Opposite of Sex (1998), Bounce (2000) and Vanilla Sky (2001). He had larger roles in the 1997 film Suicide Kings and the 2003 film Bookies, a comedy thriller film about four college students. Galecki appeared as a golfer in a 2005 episode of My Name Is Earl entitled "Stole Beer from a Golfer".