"Fantasy" received critical acclaim, with reviewers praising in its production, lyrics, Carey's vocal performance and musical progression.

The song became a global success, topping the charts in Australia, Canada, New Zealand, and the United States, and reaching the top-ten in thirteen countries.

In the US, "Fantasy" became the first song by a female artist, and second overall to debut atop the Billboard Hot 100, topping the chart for eight consecutive weeks.

After they completed the song, Carey's husband and Columbia CEO Tommy Mottola listened to "Fantasy" and agreed to include it on the album.

[4] "Fantasy" is an up-tempo song with contemporary R&B and dance-pop genres within its composition, which blends elements of funk music, hip hop, and bubblegum pop.

[15] Stephen Thomas Erlewine from AllMusic also praised the song, saying "Carey continues to perfect her craft and that she has earned her status as an R&B/pop diva.

"[5] Stephen Holden from The New York Times gave the song praise, writing "with 'Fantasy', Ms. Carey glides confidently into the territory where gospel-flavored pop-soul meets light hip-hop and recorded some of the most gorgeously spun choral music to be found on a contemporary album."

[16] Slant Magazine ranked the song at number sixty on their "Best Singles of the '90s" list, writing it is "escapism perfected, [a] summer bubblegum gem with a sweet, flawless vocal line driven by a diva in her prime.

"[17] Mark Sutherland from Smash Hits was negative, giving "Fantasy" two out of five, writing, "Unfortunately, it is also the 43rd Mariah Carey single in history to be Not Very Good At All.

[27] Strong sales led to "Fantasy" being certified sextuple-platinum by the Recording Industry Association of America (RIAA),[28] Carey's first single to do so.

[32] In Australia, the song topped the mainstream chart, and was certified triple-platinum by the Australian Recording Industry Association (ARIA).

Some of the song's R&B elements were removed for the remix, while the bassline and "Genius of Love" sample were emphasized and the bridge from the original version was used as the chorus.

[42] Carey re-recorded vocals for club remixes of the song by David Morales, titled "Daydream Interlude (Fantasy Sweet Dub Mix).

"[45] Additionally, he complimented the song, writing "At her best, as she is on this clipped, spunky track, Carey is a disco diva for the '90s, a worthy successor to trailblazing women like Donna Summer and Vicki Sue Robinson, R&B singers with an affinity for the endless groove.

On March 28, 2022, Latto released the "Big Energy" remix, which features Mariah Carey herself, along with DJ Khaled, which interpolates "Fantasy".

Afterwards, the video switches to a night time scene that involves people dancing in the parking lot and on top cars.

[4] Following in their actions, Carey joins in the festivities and hops atop a car and begins singing and dancing to the strong bass and R&B beat playing from the stereos.

[47] For the performance, Carey wore a long black trench coat and matching boots, pants and blouse, and was backed by three background vocalists.

Additionally, Carey sang "Fantasy" on the British music chart program Top of the Pops, during a promotional stop in the United Kingdom on September 12, 1995.

Carey donned a mid-waist baring white blouse and black leather pants and matching heeled boots.

[51] In 1998, it became the first time Carey performed the remix version in concert, placing a large projection screen on to the stage, and featuring snippets and cuts of Ol' Dirty Bastard throughout the video.

Additionally, Carey was dressed in blue jeans and a white blouse, and danced several chair routines with several male dancers.

Nowadays clean-cut pop stars are expected to collaborate with roughneck rappers, but when Ms. Carey teamed up with Ol' Dirty Bastard, of the Wu-Tang Clan, for the 1995 hit "Fantasy (Remix)," it was a surprise, and a smash.

[55] Moreover, Jones concludes that "Her idea of pairing a female songbird with the leading male MCs of hip-hop changed R&B and, eventually, all of pop.

"[55] John Norris of MTV News has stated that the remix was "responsible for, I would argue, an entire wave of music that we've seen since and that is the R&B-hip-hop collaboration.

"[56] Judnick Mayard, writer of TheFader, wrote that in regarding of R&B and hip hop collaboration, "The champion of this movement is Mariah Carey."

In the 1998 film Rush Hour, the character Soo Yong sings the song while it plays on the car radio, shortly before her kidnapping.

[58] In 2011, the experimental metal band Iwrestledabearonce used the song at the beginning and end of the video "You Know That Ain't Them Dogs' Real Voices".

[60][61] A remixed version of the song, with additional vocals from Jodie Comer,[62] features prominently as part of the score and the plot for the 2021 film Free Guy;[63] in the film, Jodie Comer's character Molotov Girl catches the attention of Ryan Reynolds's character Guy as she is singing the song, thus catalyzing the rest of the story.

Reynolds, who produced and starred in the film, stated that, "I am a huge Mariah Carey fan [...] It really was one of those weird things that happened naturally.