The track was written by band members Frank Iero, Matt Pelissier, Ray Toro, Gerard Way, and Mikey Way, and was produced by Benson.

The second of the two, directed by Marc Webb, was inspired by Rushmore and is structured like a movie trailer starring the band members as nerds being bullied by jocks.

The song received positive reviews from music critics, who deemed it both as a standout on Three Cheers for Sweet Revenge and of the band's discography as a whole; the track was nominated for Best Single at the 2005 Kerrang!

Despite the band's initial reluctance, they realized its potential once Gerard Way and Ray Toro performed the section of the demo, with Frank Iero recalling that "it was just the most beautiful song we ever heard".

[5] Both Matthew Butler of Drowned in Sound and a review for NME compared the track to those by Blink-182, with the former referring to it as an "exhilarating burst of snotty punk".

[23] Arielle Gordon of Pitchfork noted that its lyrics "state pent-up vindictive frustration outright", particularly the track's blunt chorus of "I'm not OK / You wear me out".

[21] Gordon praised how the song "approached the desolation in its lyrics with almost triumphant glee", noting how it avoided being self-parody by taking its message as being "deadly serious".

[30] The staff of Billboard included the track in their list of the 15 best My Chemical Romance songs, with Taylor Weatherby writing that it was "perhaps the most emo-of-all-emo anthems".

[31] Cassie Whitt and Jake Richardson, writing for Loudwire, placed the track at #2 in their ranking of the band's entire discography behind "Welcome to the Black Parade", with the latter calling it "one of the most relatable emo songs ever written".

[32] Both Margaret Farrell of Stereogum and Margaret Eloise of Louder Sound called it the band's third-best track, with the former praising its cathartic message,[33][34] while Bryant, also writing for Louder Sound, called it the band's fourth-best song, describing it as a "quite brilliant slice of angst and outsider defiance".

[14][15] Chloe Spinks of Gigwise placed the song at #7 in her ranking of the band's entire discography, writing that it "may just be the quintessential MCR track".

Lists of the 100 best emo songs in both Vulture and The Boston Phoenix included the track, with Nina Corcoran of the former highlighting how it "made the misunderstood look familiar, the goths look friendly, and depression look flattering".

[56] The video is framed as a movie trailer for what Kenneth Partridge of Billboard called the "greatest teen dramedy never made";[57] in it, the Way brothers, Toro, and Iero play "preppy, weird and croquet-playing nerds" who are being bullied by jocks.

[65] "I'm Not Okay (I Promise)" has been a staple in My Chemical Romance's performances, with Chad Childers of Loudwire reporting in 2024 that it was the band's most-played song during live sets.

[76][77] Additionally, "I'm Not Okay (I Promise)" has been covered by various artists, including by Matt Pond PA for the 2008 compilation album Guilt by Association Vol.

[16] It has also been considered a defining track of the 2000s,[86][87] with Bezer comparing it to songs like "My Generation", "Anarchy in the UK", "Smells Like Teen Spirit", and "Killing in the Name" for being a "zeitgeist-capturing, generation-defining statement".