Akers programmed Klax in just a few weeks using Amiga Basic, then ported it line-by-line to C. In a 1990 interview, he said he wanted to "produce something playable, compact and relatively quick to develop." His influences were both Tetris and tic-tac-toe. He chose the name from the sound tiles make rolling across the screen.
The prototype game ran on the same hardware as Escape from the Planet of the Robot Monsters.
Atari Games released Klax in February 1990, and soon called it a "major arcade hit". They quickly released several home versions under the Tengen brand. Akers created the Nintendo Entertainment System and Mega Drive/Genesis editions himself. Some 16-bit conversions featured improved graphics.
Klax received the Parents' Choice Foundation's seal of approval in 1990, won Best Mind Game at the 1991 European Computer Leisure Awards, and Dennis Lynch of the Chicago Tribune named it the Best Cartridge of 1990.
Midway Games gained the rights to Klax upon purchasing Atari Games in 1996. The title has been re-released in retro compilations for modern consoles. A 1999 press release called it Midway's "tic-tac tile puzzle game."
Klax's catchphrase, "It is the nineties and there is time for Klax", appears during the game's attract mode. The Game Boy Color version of the game, released in 1999, changed "nineties" to "millennium." Later versions, such as the 2005 Game Boy Advance version, still use "nineties."