The game was released on PC on 1 September 2020 and on the Xbox Series X/S and PlayStation 5 on 29 March 2022 in most regions.

The game received generally positive reviews on release, and has sold over 3 million copies as of September 2023.

[5][6] The game map is about four times more detailed than the one in Crusader Kings II and slightly larger, incorporating Europe, Africa roughly as far south as the equator, and Asia as far East as Tibet.

The characters' models change slightly to represent their age, status and health, such as having a flushed face when addicted to alcohol, and rulers of certain cultures donning a suit of armor when commanding an army.

Because of its delayed release, the pre-order bonus window was extended to 21 September exclusively for Australian Steam users.

[40] Lauren Aitken from VG247 also gave the game a perfect score, writing it is "just as bonkers, unpredictable and enthralling as its predecessor.

"[46] David Wildgoose of GameSpot praised the procedural narratives of the game saying that they are rarely as affecting and poignant as they are here; on the other hand, as a negative point, he wrote that "when the story engine isn't firing, your actions can feel rote and uninspired".

Paradox and Lab42 have been working to fix these issues by removing the 3D models in family trees and more frequent clearing of the game's cache.

[48] It was the seventh best-selling game in September 2020 in the US, and had the highest launch month sales for any Paradox Interactive title.

[49] In March 2022, Paradox Interactive announced that Crusader Kings III had sold over 2 million units worldwide.

[50] In September 2023, Paradox Interactive announced that Crusader Kings III had sold over 3 million units worldwide.

[51] In December 2020, Crusader Kings III was nominated in the Best Sims/Strategy category at The Game Awards, but lost to Microsoft Flight Simulator.