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Johnny Galecki
ACTOR

Johnny Galecki

Known for The Big Bang Theory · Family Guy · American Dad!

Johnny Galecki is a Belgian-born American actor, best known for his roles as David Healy in Roseanne, Rusty Griswold in National Lampoon's Christmas Vacation, and as Leonard Hofstadter in The Big Bang Theory.

Snapshot 2026-10-15

Born
Apr 30, 1975
Birthplace
Bree, Belgium
Known For
Acting

Biography

Johnny Galecki is a Belgian-born American actor, best known for his roles as David Healy in Roseanne, Rusty Griswold in National Lampoon's Christmas Vacation, and as Leonard Hofstadter in The Big Bang Theory.

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Known For

TVThe Big Bang Theory
The Big Bang TheoryLeonard Hofstadter · 2007
★ 7.9
TVFamily Guy
Family GuyLeonard Hofstadter (voice) · 1999
★ 7.4
TVAmerican Dad!
American Dad!Arnie (voice) · 2005
★ 7.0
TVMy Name Is Earl
My Name Is EarlScott · 2005
★ 7.6
TVEntourage
EntourageJohnny Galecki · 2004
★ 7.4
TVBatman Beyond
Batman BeyondKnux (voice) · 1999
★ 8.2
TVThe Late Show with Stephen Colbert
The Late Show with Stephen ColbertSelf - Guest · 2015
★ 6.1
TVConan
ConanSelf · 2010
★ 7.2

Filmography

Movies

Murder OrdainedDoug Rule
1987
A Night in the Life of Jimmy ReardonToby Reardon
1988
National Lampoon's Christmas VacationRusty Griswold
1989
PrancerBilly Quinn
1989
In Defense of a Married ManEric
1990
Backfield in MotionTim Seavers
1991
Sudden FuryDaniel Hannigan
1993
Without ConsentMarty
1994
Murder at My DoorTeddy McNair
1996
BeanStingo Wheelie
1997
I Know What You Did Last SummerMax Neurick
1997
Suicide KingsIra Reder
1997
The Opposite of SexJason Bock
1998
BounceSeth
2000
Playing Mona LisaArthur
2000
Morgan's FerryDarcy
2001
Vanilla SkyPeter Brown
2001
BookiesJude
2003
ChrystalBarry
2004
Happy EndingsMiles (uncredited)
2005
HancockJeremy
2008
Table for ThreeTed
2009
In TimeBorel
2011
CBGBTerry Ork
2013
Must See TV: An All Star Tribute to James BurrowsSelf
2016
RingsGabriel Brown
2017
The CleansePaul Berger
2018
The CleanseProducer
2018
A Dog's JourneyHenry Montgomery
2019
Unraveling the Mystery: A Big Bang FarewellSelf - Host
2019
The Little Dog LaughedAlex
2020
I'm Chevy Chase and You're NotSelf
2025

Television

People's Choice AwardsSelf - Presenter · 1 eps
1975
Entertainment TonightSelf · 2 eps
1981
RoseanneDavid Healy · 92 eps
1988
Hardball1 eps
1989
American DreamerDanny Nash · 17 eps
1990
Blind FaithJohn Marshall · 2 eps
1990
BlossomJason · 1 eps
1990
Civil WarsGreg Stolbach · 1 eps
1991
BillyDavid MacGregor · 13 eps
1992
Batman BeyondKnux (voice) · 1 eps
1999
Family GuyLeonard Hofstadter (voice) · 1 eps
1999
The Norm ShowDale Stackhouse · 2 eps
1999
Hope & FaithJay · 3 eps
2003
The Ellen DeGeneres ShowSelf · 1 eps
2003
EntourageJohnny Galecki · 3 eps
2004
LAXLeland Pressman · 1 eps
2004
American Dad!Arnie (voice) · 1 eps
2005
My Name Is EarlScott · 1 eps
2005
The Late Late Show with Craig FergusonSelf · 1 eps
2005
BO
Boulevard of Broken DreamsSelf (archive footage) · 1 eps
2007
The Big Bang TheoryLeonard Hofstadter · 279 eps
2007
ConanSelf · 1 eps
2010
ConanSelf - Guest · 1 eps
2010
The TalkSelf · 1 eps
2010
Lip Sync BattleSelf · 1 eps
2015
The Late Show with Stephen ColbertSelf - Guest · 1 eps
2015
SciJinksSelf - Host · 8 eps
2018
SciJinksExecutive Producer
2018
The ConnersDavid Healy · 4 eps
2018
Stars in the HouseSelf · 1 eps
2020
PS
Peep ShowMark · 1 eps

Photos

Johnny Galecki photo
Johnny Galecki photo
Johnny Galecki photo
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