Tucker Carlson, a source of repeated controversies, is out at Fox News.

Fox News said Monday that it was ending its relationship with Tucker Carlson, its most popular prime time host and one of the most influential voices on the American right.

Mr. Carlson’s departure stunned people inside Fox News and the larger conservative media world, where he has had power like few others to elevate candidates and controversies on his 8 p.m. show, “Tucker Carlson Tonight.” The program became a must-watch for…