By December 2015, planning for a new Super Smash Bros. game had begun, with full development starting after the completion of 3DS/Wii U‘sdownloadable content (DLC). Series creator and director Masahiro Sakurai returned along with Bandai Namco Studios and Sora, the studios that developed 3DS/Wii U. The return of the studios sped up the preparation process. Sakurai’s goal with Ultimate was to includ e every character from previous games despite the various development and licensing problems this would cause. Various well-known video game music composers contributed to the soundtrack, with Hideki Sakamoto writing the main theme, “Lifelight”. The game has been supported post-release with DLC that adds new characters, stages, and music.

Nintendo teased Ultimate in March 2018 and revealed it at E3 2018 the following June. It was released worldwide on December 7, 2018. The game received universal acclaim, with some critics calling it the best of the series. They praised its amount of content and fine-tuning of existing Smash gameplay elements, although its online mode received some criticism. By March 2019, the game had sold over 13.81 million copies worldwide, making it the fastest-selling Switch game and one of the bestselling fighting games of all time.