Millions of people have watched a Jan. 11 video by YouTube’s biggest star that included two men laughing as they held a banner that read, “Death to all Jews.”

The man behind the video is Felix Kjellberg, a 27-year-old Swede known as “PewDiePie,” who has amassed 53 million subscribers. His success has brought him multimillion-dollar deals from YouTube and Walt Disney Co., which owns a firm that runs Mr. Kjellberg’s business.

Since August, PewDiePie has posted nine videos that include anti-Semitic jokes or Nazi imagery, according to a review of his channel by The Wall Street Journal.

On Monday after the Journal contacted Disney about the videos, the entertainment giant said it was severing ties with Mr. Kjellberg, who as PewDiePie rose to prominence via clips of himself playing videogames or performing skits and making crude jokes.

Under the terms of their arrangement, Mr. Kjellberg had editorial independence.