Meier partnered with Jeff Briggs and Brian Reynolds, both former MicroProse employees, to found Firaxis Games. The new company provided a more focused and creative environment for Meier's game design ambitions.

Civilization II saw further improvements to the original Civilization game, although this was principally Brian Reynolds' work rather than Sid Meier's.

Alpha Centauri was a science fiction strategy game set on a newly colonized planet. It expanded upon the Civilization formula with new factions, technologies, and a compelling narrative exploring philosophical themes.

Civilization III marked the first major iteration of the Civilization franchise under Firaxis's guidance. It introduced new gameplay mechanics and refined the core experience.

Civilization IV brought significant graphical and gameplay improvements to the series, introducing religion and a new diplomacy system. It continued the franchise's critical and commercial success.

Civilization V introduced hex-based tiles and a new combat system, further evolving the gameplay formula and enhancing the strategic depth of the game.

Civilization VI introduced districts, which allowed cities to expand beyond their central tile. It also improved the diplomacy and added environmental effects, all of which added further depth and enjoyment to the Civilization gaming experience.

Sid Meier remains actively involved with Firaxis Games, serving as the Director of Creative Development. He continues to contribute to the design and development of new games and expansions within the Civilization and other Firaxis franchises.