For a long time, George Clooney was just another handsome rake who turned up in guest shots on TV. But his five seasons on 'ER' changed all that. Not only did his role as likable cad Dr. Doug Ross make him a household name, but it also made feature film casting directors reassess him as leading man material.

To put it mildly, Clooney's scored big in that kind of role, and has used his good looks, native intelligence, good humor and smoldering stare to manage a dual career as a serious dramatic actor and a good-time comedic lead. Clooney is unafraid to tackle films that ask serious questions about the world of politics and power. He also knows how to pick vehicles that will sell tons of popcorn.

With the release of the assassination thriller 'The American,' here's betting he does both -- just as he did in varying degrees with these, his 10 best films:

10. From Dusk Till Dawn (1996)
With 'ER' a ratings winner, Clooney caught the eye of Robert Rodriguez, who directed this horror flick written by Quentin Tarantino. Clooney plays Seth Gecko, a lowlife who's on the lam after a bank robbery, and stops off in a strip club that just happens to be full of vampires. (Dontcha hate that?) Since this is a horror flick, the rules dictate that Clooney eradicate as many of them as possible, which he does in graphic, bloody style (a.k.a. the Tarantino Rules). A tongue-in-cheek thriller that helped further solidify Clooney's devil-may-care screen persona.
From Dusk Till Dawn Movie Poster
From Dusk Till Dawn
Based on 15 critics

On the run from a bank robbery that left several police officers dead, Seth Gecko (George Clooney) and... Read More

Out of Sight Movie Poster
Out of Sight
Based on 30 critics

Meet Jack Foley (George Clooney), the most successful bank robber in the country. On the day he busts... Read More

Three Kings Movie Poster
Three Kings
Based on 34 critics

Just after the end of the Gulf War, four American soldiers decide to steal a cache of Saddam Hussein's... Read More

O Brother, Where Art Thou? Movie Poster
O Brother, Where Art Thou?
Based on 30 critics

Ulysses Everett McGill (George Clooney) is having difficulty adjusting to his hard-labor sentence in... Read More

Ocean's Eleven Movie Poster
Ocean's Eleven
Based on 35 critics

Dapper Danny Ocean (George Clooney) is a man of action. Less than 24 hours into his parole from a New... Read More

Confessions of a Dangerous Mind Movie Poster
Confessions of a Dangerous Mind
Based on 33 critics

Game show television producer Chuck Barris (Sam Rockwell) is at the height of his career. His creation,... Read More

Good Night, and Good Luck. Movie Poster
Good Night, and Good Luck.
Based on 41 critics

When Senator Joseph McCarthy begins his foolhardy campaign to root out Communists in America, CBS News... Read More

The Good German Movie Poster
The Good German
Based on 34 critics

Jake Geismar (George Clooney), an Army correspondent, helps his former lover, Lena Brandt (Cate Blanchett),... Read More

Michael Clayton Movie Poster
Michael Clayton
Based on 36 critics

Former prosecutor Michael Clayton (George Clooney) works as a "fixer" at the corporate law firm of Kenner,... Read More

Up in the Air Movie Poster
Up in the Air
Based on 36 critics

An idea from a young, new co-worker (Anna Kendrick) would put an end to the constant travel of corporate... Read More

The American Movie Poster
The American
Based on 36 critics

When an assignment in Sweden ends badly, master assassin Jack (George Clooney) retreats to the Italian... Read More