Farrell subsequently had a number of small parts in various TV shows and movies, until 2000, when he was cast in the part of "Private Roland Bozz" in Tigerland, an American film directed by Joel Schumacher. Although the film received only a limited release in the United States, Farrell has since been cast in a number of high-profile productions, and is considered one of Ireland's rising stars in Hollywood. Farrell's first American films, "American Outlaws" (2001) and Hart's War (2002), were not commercially successful, but his 2003 films, including The Recruit, S.W.A.T. and Phone Booth, were well received and were box office successes, cementing Farrell as a commercial draw.[1] Although he has a thick Irish accent, Farrell uses a western accent in both American Outlaws and his breakthrough role Tigerland. Farrell is also a proven supporting actor, given his performances as a cop who chases after potential criminal Tom Cruise in Minority Report (2002) and as the villain Bullseye in Daredevil (2003).

In 2004, Farrell appeared in several films that received only a limited theatrical release, including Intermission and A Home at the End of the World, both of which received some positive reviews. According to press reports, Audiences at a test screening of "World" were visibly distracted (with audible gasps) by a brief frontal nude scene of Farrell, during which he walked naked down a hallway. The film's producers claimed to have deleted this scene due to the threat that it might distract viewers from the real content of the film. The removed clip was later leaked to the internet.

Farrell appeared in the title role of 2004's Alexander, which was considered a financial and critical disaster. Farrell's performance as Alexander the Great was heavily criticized, with particular attention given to his peroxided hair and strong Irish accent. His next film was 2005's The New World, also a historical epic that was met with mixed reviews. The film was released on a limited number of screens and had a low box office gross.

Farrell was married to English actress Amelia Warner from July 2001 to November 2001. He later had a son, James (born September 12, 2003), with Los Angeles-based native Kim Bordenave.

Farrell is sometimes known for his reported sexual promiscuity, habitual use of profanity, extreme heavy drinking, and chain smoking. Crew and cast members of Phone Booth reported him smoking over six packs of cigarettes a day. His heavy use of profanity during interviews is often edited from his talk show appearances. He is rumoured to be dating up-and-coming actress Lake Bell.

In December 2005, Farrell voluntarily checked into a treatment center for dependency to prescription painkillers. His publicist commented that Farrell was originally given pills for dealing with back injury pain. He was released in January 2006. In May 2006 Colin started attending AA meetings.

Farrell maintains a home in Ringsend in his native Ireland while not travelling frequently for work. He often says that "Ireland is home" and that "all [his] friends are there".

Farrell sparked gay rumors in 2005 when he was caught giving a relatively brief kiss to Argentinian soccer player Diego Maradona, on the mouth, in a Buenos Aires bar. He got tongues wagging when he was photographed with and rumored to have hooked up with a drag queen named Elaine Lancaster.

In July 2005, Farrell sued his former girlfriend, Playboy Playmate Nicole Narain, adult Internet company Internet Commerce Group (ICG), and porn producer David Hans Schmidt over the rights to a nearly-fifteen minute sex tape that Farrell had made with Narain in 2003. The tape was made at Narain's apartment and features the two engaged in intercourse and oral sex. Farrell claims he understood the tape as being "strictly private and confidential between them," but it was leaked to Schmidt and ICG who tried to release it publicly. A Los Angeles judge issued a temporary restraining order barring the sale, distribution, or display of the tape. In the past, Schmidt had distributed or tried to distribute nude material of other celebrities, including Tonya Harding, Paula Jones, and Fred Durst.

Narain claimed that she did not give the tape to anyone and was not sure if or how copies were taken from her. She had originally said that she would work with Farrell to ensure that it remained private, but Farrell claimed the opposite, and said Narain was trying to release it along with Schmidt, a claim Narain denies. Part of the conflict may have also come when Narain refused to grant full ownership of the tape to Farrell. Later in an appearance on MSNBC, Narain said that she and Farrell should commercially release the tape together themselves to "take control of the situation" after parts were leaked to the Internet.

In January 2006, the tape surfaced on a website called dirtycolin.com. The site was shut down on the same day because of server overload, but re-opened a week later. The tape was then pirated through BitTorrent and other file sharing systems. Both Farrell's and Narain's lawyers denounced the site, which was shut down again a few days later for unknown reasons. Farrell's legal team said it would take legal action against sites that hosted the tape. A trial date for the Narain lawsuit was set for July 17th, 2006, but the judge allowed Farrell and Narain to mediate until April 20th. On April 16th, the two reached a settlement with confidential terms. However, Farrell's lawsuit against ICG continued with a trial date set for July 21th.