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 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.

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.

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.