Following the shutdown of Nintendo Network on April 8, 2024, two players by the user handles of Marioiscool246 and Fishguy6564 attempted to stay connected to the service in some form by activating online multiplayer in Mario Kart 7 and playing for as long as possible. The campaign, which originated as a way to determine how Nintendo Network functionality is disabled for a given title, used bots and a custom patch to keep the pair's 3DS systems connected and active.

While Marioiscool246's 3DS eventually froze after just over a month, Fishguy6564 remained live for substantially longer, with his own system not crashing until November 3, 209 days later. In doing so, he broke the record for the longest recorded time spent in post-shutdown online multiplayer, surpassing both the 25-day stretch held by Halo 2 player APACHE_N4SIR in 2010 and the 68-day Splatoon marathon conducted by Lcd101 earlier in 2024.

According to environment artist Ted Anderson in an interview with YouTuber KIMI TALKZ, Retro Studios was apparently hesitant on working with Nintendo to create the game:

The icon used in the Download Play app when downloading data for the game is a cruder, early version of the icon used for the final game. For unknown reasons, this discrepancy was fixed only in the Chinese release of the game.

A portion of the Bowser's Castle theme is remixed from Mario Kart: Double Dash!!'s Bowser's Castle theme.

Inside the game's files is an unused soccer ball. It's likely this could've been used for testing the models, or it could've been used for one of the Wuhu Island stages.

The retro courses from Mario Kart DS have been widened in this game while retro courses from the other games have all been shortened.

Each of the Retro Cups feature one course each from both Mario Kart DS and Mario Kart Wii.

The Music that plays during Neo Bowser City (Koopa City in the PAL Regions) consists of music from other Mario Kart Tracks. These include:

• Toad/Mario Circuit from Mario Kart 7.
• The Title Screen from Mario Kart 7.
• Toad's Turnpike from Mario Kart 64.
• Luigi/Mario Circuit from Mario Kart Wii.

The results theme is a remixed version of the theme from Mario Kart 64.

On the Piranha Plant Slide/Pipeway track, the clouds are recolored bushes. This is a nod to the original Super Mario Bros. where the bushes and clouds are the same art with different palettes.

The game's initial lineup of playable characters, prior to unlocking more, are the original 8 playable characters from Super Mario Kart on the SNES.

In the European version of the game the track called "Music Park" in the American and Japanese version is called "Melody Motorway". Despite the name change, the American/Japanese name "Music Park" can still be seen on banners in the level in the European version.

On the track "Rosalina's Ice World", the Comet Observatory and the starting planet from the Gateway Galaxy from Super Mario Galaxy can be seen in the background.

On March 15th 2012, Nintendo released a patch that stopped a glitch which let you skip a large portion of Wuhu Loop. This patch only covers the Online Multiplayer and not the Time Trials.

Activating the Lucky 7 item underwater causes the blooper to leave a trail of ink bubbles.

In Shy Guy Bazaar, the carpets have sprites of Angry Suns, Phantos, Pansers and Cobrats from Super Mario 2 and 3 on them.