In the English release of Street Fighter II, one of Ryu's quotes to defeated opponents is "You must defeat Sheng Long to stand a chance." "Sheng Long" is a mistranslation of Ryu's flying uppercut move Shōryūken (昇龍拳) stemming from the first two Japanese characters meaning "shēng lóng" in Chinese pinyin. As a result, players mistakenly thought that Ryu was referring to a person named Sheng Long instead of his Shōryūken, and that he was a secret playable character.

Amidst a swarm of fan mail to gaming publications asking how to unlock Sheng Long, the American magazine Electronic Gaming Monthly published a guide to fight him as a secret boss for their annual April Fools' prank in 1992. Photoshopped screenshots of Sheng Long fighting Ryu were created by editor Ken Williams, who also wrote "ridiculous requirements" to find him that were meant to imply he was not real, but were actually attempted by players. In response to complaints, they revealed at the end of the year that Sheng Long was a hoax, and expressed surprise over it gaining worldwide coverage as other publications in Eurasian countries reprinted the guide without their permission.

Sheng Long was brought back for a second April Fools' prank in 1997 in response to rumors that he could be in Street Fighter III, creating hand-drawn art of him and claiming he was the localized version of the real non-playable character Gouken. Despite adding more obvious clues to it being a prank, according to the magazine's June 1997 issue, this second prank was so convincing that Capcom of America allegedly fell for it and called their Japanese headquarters to ask why they were not told he was in the game.

Sheng Long left a continuing influence on video game hoaxes and the Street Fighter series, leading to a scrapped official appearance in the game adaptation of Street Fighter: The Movie, and Capcom pulling their own Sheng Long pranks in 2008 and 2017. In 2023, Sheng Long made his first canonical appearance in the series in Street Fighter 6 as a non-playable opponent using Ryu's fighting style, and can be fought in the World Tour mode after completing the game.

Street Fighter 6 is the first mainline title in the Street Fighter series to include third party guest characters, as Terry Bogard and Mai Shiranui from SNK's Fatal Fury series were revealed to be coming to the game as part of the Season 2 DLC wave. According to an interview with Famitsu, talks about such a collaboration first began at EVO 2022, where the two companies celebrated by exchanging posters featuring the other's characters drawn by their own artists. When asked why they specifically went with Terry and Mai, director Takayuki Nakayama stated:

When Street Fighter 6's preliminary logo was revealed, it was mocked for a variety of reasons, particularly a disconnect from previous series logos and aligning with a widely criticized trend of generic, minimalist or "oversimplified" logos. Some fans noted that the logo strongly resembled an $80 design for an "SF" logo posted on the Adobe Stock Image store by user xcoolee, which had previously been used for a sci-fi convention in France. xcoolee did offer to sell exclusive rights to the logo to Capcom, but was seemingly denied. It was also discovered that a Taiwanese electronics and appliances retailer, Sunfar, had a similar hexagonal logo. On the day after Street Fighter 6's logo reveal, the front page of their website displayed an advertisement with the logo featuring a paint splatter reading the number 6 promoting gaming products, most likely as a promotional parody. It is unknown if either resemblance was a coincidence on Capcom's part, and xcoolee did not state if they knew whether Capcom bought anything from their store or not. The logo of Street Fighter 6 would be updated to appear more stylized before the game's launch in response to the negative reception, although the fan reception to the new logo was not much more positive.

According to English voice actor Aleks Le in his YouTube video "LUKE SINGS TMNT THEME SONG (OFFICIAL) SF6", he stated that in February 2023, he had dinner with the game's director Takayuki Nakayama, who said that he and his team really loved Le's passion and watching all the cool and funny things he did with the character both in-game and online. Nakayama then asked Le if he could get Luke to sing a song, to which he replied: "Me? No, I don't know how to sing... But Luke? Even if he's bad..." Nakayama's idea was to recruit Le to sing the lyrics to a new arrangement of the Teenage Mutant Ninja Turtles theme song, arranged by CAP-JAMS to promote Street Fighter 6's TMNT DLC. Le commented that this performance was his first time trying to sing and that his vocal coach for the recording sessions was Jason Miller, who provided vocals for the song "Rules of Nature" from Metal Gear Rising: Revengeance.

According to Luke's English voice actor Aleks Le, Luke was originally supposed to say "Yes! I won!" for one of his victory poses. However, Le was against this since he found the line to be generic and instead suggested "Woo! Let's go", taking inspiration from the Street Fighter competitive scene, where the phrase "let's go" is often heard. Voice director Jonathan Klein was against it since he didn't understand it, but after hearing Le's performance he accepted the change.

When Rashid was unveiled as a playable character in Street Fighter V, his specific nationality was unknown, with players only knowing that he was Middle Eastern. However, in 2022 when the entire playable base game roster and first wave of DLC of Street Fighter 6 was leaked, it revealed a more specific country he was from, with Rashid confirmed as being Saudi Arabian.

On a Street Fighter 6 developer Q&A stream, the team confirmed that the idea of having JP using Bartitsu (mistakenly referred to as Baritsu) was inspired by Sherlock Holmes. Said martial art's appearances in Sherlock Holmes stories inspired the staff to create a character that fought using a cane.

Cammy's level 2 Super is inspired by a scene from Street Fighter II: The Animated Movie. In the scene, Cammy grabs British Minister of Justice Albert Sellers by the collar, leaps up onto his shoulders, twists around, snaps his neck, then comes down and kicks his knees out from behind. This move is performed by Cammy in the game.

The background of the World Tour intro features a dollar bill with a portrait of Dr. Light, from Mega Man, as a founding father.