Following his breakout performance as Dr. Doug Ross on the hit television show ER, George Clooney hit the ground running and has yet to stop. Whether he is in front or behind the camera, Clooney has become a master of his craft. Starring in some of the best movies and iconic roles in Hollywood history. The megastar has an impressive resume to his credit, but has certainly left many opportunities on the table as well. These are the top ten roles George Clooney turned down or didn't get.

10 John McLoughlin - World Trade Center (2006)

Nicolas Cage in World Trade Center
Paramount Pictures

World Trade Center serves as director Oliver Stone's dramatic retelling of the devastating 9/11 terrorist attack on the World Trade Center in New York. Featuring Nicolas Cage in the lead role as Sergeant John McLoughlin, a New York City firefighter, the movie serves as a harrowing tribute to those lost in the attack and those who worked to save as many as they could. Before Cage signed on to the film, it was George Clooney who had been offered but ultimately turned down the role, opting to star in The Good German in 2006.

9 Will - About a Boy (2002)

Hugh Grant and Nicholas Hoult on a couch in About A Boy
StudioCanal

Nobody does early 2000s romantic comedies quite like actor Hugh Grant. 2002's About a Boy is no different as Grant shines as he often does in the lead role of Will Freeman. Among the list of actors considered for the role included George Clooney, whose star power hadn't quite reached its peak yet in 2002.

8 Robert Langdon - The Da Vinci Code (2006)

Audrey Tautou and Tom Hanks
Sony Pictures.

Based on the Dan Brown novel of the same name, The Da Vinci Code delighted audiences in 2006 by leading them on a mystery fueled, albeit religiously controversial, adventure through Europe. While it was Tom Hanks' performance and rocking long hair that helped make the film a success, the part almost went to George Clooney, who was a name considered to take on Langdon before Hanks landed the role.

Related: Best Film Scores of the 2000s

7 Director - Frost/Nixon (2008)

kevin-bacon-frost-nixon (1)
Imagine Entertainment

George Clooney coveted the director role when it came to the 2008 film, Frost/Nixon. Telling the playwright whose work the film was based on how badly he desired to direct the film. Ultimately, the directors' chair went to Ron Howard, who would go on to help make one of the best movies about American presidents.

6 J.D. - Thelma and Louise (1991)

Thelma and Louise
Metro-Goldwyn-Mayer

Thelma and Louise is a movie that helped launch the career of superstar and real-life friend of George Clooney, Brad Pitt. It very well could have helped to jumpstart Clooney's career as well, long before ER. Having auditioned five times for the part of J.D., Clooney was still passed up for the role that was eventually filled by Pitt.

5 Artemus Gordon - Wild Wild West (1999)

Wild Wild West 1999
Warner Bros. Pictures

In what was meant to be the next big blockbuster film, Wild Wild West hit theaters in 1999 and starred Will Smith and Kevin Cline in this big-screen adaptation of the 1960s television series of the same name. Before Kline was cast in the role of sidekick to James West, George Clooney was considered for the film and ultimately did not get the role, something he may look back on fondly given the reception to the movie overall. Even megastar Will Smith admits to this day that Wild Wild West is a thorn in his side.

4 Mr. Blonde - Reservoir Dogs (1992)

Reservoir Dogs Mr Blonde
Miramax Films

Having worked alongside Quentin Tarantino in From Dusk Till Dawn, George Clooney has sadly never been cast in one of Tarantino's directed projects. This is not due to lack of trying, as Clooney auditioned for the role of Mr. Blonde in Tarantino's directorial debut and breakout feature film, Reservoir Dogs. The part of Mr. Blonde would end up going to Michael Madsen.

Related: Reservoir Dogs: 5 Iconic Scenes in the Quentin Tarantino Movie

3 Sands - Once Upon a Time in Mexico (2003)

Once Upon a Time in Mexico
Miramax
Sony Pictures Motion Picture Group

Having worked with the actor previously, George Clooney was Robert Rodriquez's first choice to play C.I.A. Agent Sands in his 2003 movie, Once Upon a Time in Mexico. The third film in Rodriquez's Mexico Trilogy, serves as a follow-up movie to 1992's El Mariachi and 1995's Desperado. Clooney would ultimately turn down the role of Sands, who would go on to be played by Johnny Depp.

2 Carl Denham - King Kong (2005)

Jack Black as Carl Denham in King Kong (2005)
Universal Pictures

It was director Peter Jackson who made his intentions known that he wanted either Robert De Niro or George Clooney to take on the role of filmmaker Carl Denham in his epic 2005 remake of King Kong. While neither man would accept the role, Jack Black would go on to give a top-tier performance in the highly praised movie.

1 Batman - Batman Triumphant

Bat Nipples from the Batman Nipple Suit worn by George Clooney in Batman & Robin
Warner Bros.

If you are unfamiliar with the scrapped sequel to Batman & Robin, known as Batman Triumphant, it is truly a fantastical story. The film would not only have featured the returns of all previous villains, including Jack Nicholson's Joker, Jim Carrey's The Riddler, and Danny DeVito's Penguin. It also would have returned George Clooney to the lead role of the caped crusader. Given that Batman & Robin already had a soured reputation for being one of the worst sequels ever made. It was probably in Clooney's best interests that this Frankenstein's monster of a project never came to be.