
Acting
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.

I'm Chevy Chase and You're Not
as Self

The Little Dog Laughed
as Alex

A Dog's Journey
as Henry Montgomery

Unraveling the Mystery: A Big Bang Farewell
as Self - Host

The Cleanse
as Paul Berger

Rings
as Gabriel Brown

Must See TV: An All Star Tribute to James Burrows
as Self

CBGB
as Terry Ork

In Time
as Borel

Table for Three
as Ted

Stars in the House
as Self · 1 ep.

The Conners
as David Healy · 4 ep.

SciJinks
as Self - Host · 8 ep.

The Late Show with Stephen Colbert
as Self - Guest · 1 ep.

Lip Sync Battle
as Self · 1 ep.

Conan
as Self - Guest · 1 ep.

The Big Bang Theory
as Leonard Hofstadter · 279 ep.
Boulevard of Broken Dreams
as Self (archive footage) · 1 ep.

American Dad!
as Arnie (voice) · 1 ep.

My Name Is Earl
as Scott · 1 ep.
Vanilla Sky
2001