Comcast Corp. said it is no longer pursuing an acquisition of several key media and entertainment assets from 21st Century Fox, leaving Rupert Murdoch’s media empire in position to finalize a deal with Walt Disney Co.

The Philadelphia-based cable and programming giant had approached 21st Century Fox about assets that included its international properties, movie and television studios, and some U.S. cable networks, The Wall Street Journal had previously reported, citing people familiar with the matter.

“When...