It peaked at number two on the Billboard Hot 100 and topped the charts in the United Kingdom, Canada, Ireland, New Zealand, and several other countries.

The band and their record company then decided to remove the physical single from music stores in the country (while keeping the download available) so people would "remember the song fondly and not get sick of it".

The song won a Grammy Award for Best Urban/Alternative Performance in 2007 and was also nominated for Record of the Year, which it lost to "Not Ready to Make Nice" by Dixie Chicks.

[citation needed] "Crazy" was performed at the 2006 MTV Movie Awards, with Danger Mouse and Green dressed as various Star Wars characters.

Danger Mouse's manager sent the song to Downtown's A&R Josh Deutsch because they were looking for an independent label with the same resources as a major.

"[15]By the time the record was signed to Downtown, there was already a huge swell of anticipation, in part due to the established reputation of the two artists but even more as a result of the demo being played on BBC Radio 1 and sparking a profound online awareness.

[15] Musically, "Crazy" was inspired by film scores of Spaghetti Westerns, in particular by the works of Ennio Morricone,[16] and the song "Last Men Standing" by Gian Piero Reverberi and Gian Franco Reverberi from the 1968 Spaghetti Western Django, Prepare a Coffin, an unofficial prequel to Django.

So we started jokingly discussing ways in which we could make people think we were crazy... CeeLo took that conversation and made it into 'Crazy', which we recorded in one take.

[19] In 2007, "Crazy" was named the best single of 2006 by The Village Voice's Pazz & Jop annual year-end critics' poll.

Despite its official removal, record shops had enough stock remaining to sell 19,827 physical copies; along with download sales, this kept the song at number two in the chart week ending date June 10, 2006.

"Crazy" also performed strongly outside Europe, with top-five positions on the New Zealand and Australian Single Charts, and was also certified gold in both countries.

The Discount Rhinos Full Control remix of the track also featured in the top 20 of the Australian ARIA Club chart.

Going along with the psychiatric theme of the song, Gnarls Barkley's music video for "Crazy" is done in the style of the Rorschach test.

Both Cee-Lo and Danger Mouse appear in the shapes, as do the duo's gunshot/heart logo, "Satan", a cranium and various animals, including centipedes, birds, bats, spiders, and insects.

This early promo, directed by Mina Song, is also completely animated and features several symbols from many cultures and religions that appear in a disjointed harmony to the lyrics.

"Crazy" was used in several films and TV shows including Kick-Ass, I Think I Love My Wife, Religulous, The Big Short, Cold Case, How to Rock, Grey's Anatomy, Medium, Boyhood, and It's Always Sunny in Philadelphia.

Violent Femmes released a cover of the song on June 24, 2008, through the iTunes Store[118] and on a limited edition, baby blue 12" vinyl.

"[120] The Violent Femmes hosted a YouTube contest beginning on June 10, 2008, with a cash award of one thousand dollars and "other cool prizes" for creating and submitting a promotional video clip.

Other artists, including Maroon 5, Ninet Tayeb, The Raconteurs,[126] Billy Idol,[127] The Academy Is... (with Travie McCoy of Gym Class Heroes),[128] Butch Walker,[129] Cat Power,[130] Texas,[128] The Twilight Singers,[128] Mates of State,[131] Paco Estrada & One Love, and of Montreal[132] have performed cover versions of the song live in concert.

On November 6, 2008, the band OneRepublic covered "Crazy" in front of a hometown crowd at the Fillmore Auditorium in Denver, Colorado.

On February 28, 2019 Kacey Musgraves performed "Crazy" live with CeeLo Green during the second Nashville show of the Oh, What a World Tour at the Ryman Auditorium.

Similarly, many unofficial remixes and mashups of the song were released as white label records and are circulating on file sharing networks and MP3 blogs.

The Discount Rhinos Full Control remix of the track even reached number 15 of the Australian ARIA Club chart.