[5] The game features characters who have appeared in previous installments, including Mario, Luigi, Princess Peach, Yoshi, Toad, Donkey Kong, and Bowser, in addition to characters such as Rosalina, Funky Kong, and Dry Bowser who are playable for the first time.

For example, the Jetsetter (also known as the Aero Glider in PAL regions) must be unlocked by earning a one-star rank or higher on all 150cc Retro Cups in Grand Prix mode.

[7][8] Mario Kart Wii features multiple game modes: Grand Prix, Time Trials, Versus, and Battle.

Battle mode is similar to that seen in previous installments in which players drive around an enclosed arena and attack each other using items.

The Mario Kart Channel also offered additional online information, including regional or worldwide rankings for Time Trials, and monthly Nintendo-sponsored tournaments with special objectives.

[14] Hideki Konno, who worked with the Software Development Department of Nintendo's Entertainment Analysis & Development (EAD) division and had previously worked on the first two Mario Kart games as well as Mario Kart DS, served as the game's producer.

Shigeru Miyamoto acted as "General Producer" and gave miscellaneous advice on various aspects of the game.

[15] The game was the first in the series to feature BMX motorbikes as drivable vehicles, an idea which Konno had proposed since Double Dash out of his passion for extreme sports but was rejected due to the seemingly bizarre image of Mario riding a bike.

[16] The game was briefly known internally under the name "Mario Kart X" before its final name was decided upon, referring to the "X" in the word "extreme".

[17] Mario Kart Wii was officially announced at E3 2007; the online features and the first footage of the game were shown at the Expo.

[18] During Nintendo of America CEO Reggie Fils-Aimé's presentation, he unveiled the game via a trailer that showed some of the new characters and tracks.

Additional details of the game were later released in conjunction with the Nintendo Fall 2007 Conference held in October 2007, where it was revealed that it would include bikes and the Wii Wheel.

The designers tested roughly 30 different prototypes of the wheel with different shapes, colors, and weights based on real-life go-karts.

The final design for the wheel was made to be as lightweight as possible for it to suit long-term periods of gameplay, and it was made entirely white despite experimentation with two-colored designs for it to fit with the color scheme of previous peripherals such as the Wii Zapper and the Wii Balance Board.

During the extensive testing of the different Wii Wheel prototypes, the developers decided to have the voice actors play the game during recording sessions.

[22] Reviewers deemed the gameplay to be familiar and more safe and predictable than that of Mario Kart: Double Dash.

[24][30][32] Official Nintendo Magazine commented that the Wii Wheel worked very effectively and loved the different multiplayer modes.

[38] Lark Anderson of GameSpot praised the game for being easy to jump into for players of any skill level and stated that motorcycles provide a great alternative to go-karts.

[24][27][30][31] The unbalanced items and rubber band AI, which were said to result in chance-influenced gameplay, were a common point of criticism,[27][28][30][32][31][33] as was the truncation of the battle mode from previous titles.

[40] The staff of IGN ranked the game #18 in their 2019 list of "Top 25 Favourite Kart Racers", deeming it "yet another solid entry in the series" and saying that its expanded track roster and inclusion of both online and splitscreen multiplayer gameplay made it "one of the system’s go-to party games".

[42] The tracks Maple Treeway and Coconut Mall have been ranked among the series' best,[43][44][45][46] while Matthew Wilkinson of Screen Rant respectively ranked Rainbow Road, Wario's Gold Mine, and Moonview Highway as the first, eighth and ninth most difficult tracks in the series.

[48] In the week ending May 4, 2008, Mario Kart Wii had sold over a million copies in Japan alone, less than a month since its release in the region.

[50] In the United States, Mario Kart Wii was the second-best-selling video game in April 2008, selling 1.12 million copies, according to the NPD Group; putting it behind the Xbox 360 version of Grand Theft Auto IV and ahead of the PlayStation 3 version, both released in the same week.