Reddit, one of the most highly trafficked websites in the world, is replacing its interim chief executive, Ellen Pao, ending an eight-month tenure that was enmeshed in controversy.

Ms. Pao is resigning and being replaced by co-founder and former chief Steve Huffman, the company said. He will rejoin Reddit’s other co-founder, Alexis Ohanian, who has returned to the company’s San Francisco headquarters full-time.

The move comes just days after Ms. Pao apologized to users for mishandling last week’s firing of Victoria Taylor, Reddit’s director of talent. Ms. Taylor was a key contact for the site’s moderators, mostly volunteers who manage nearly 10,000 discussion boards, or subreddits.

Ms. Taylor’s dismissal provoked a user revolt, as moderators shut down hundreds of subreddits. A petition on the social-causes website Change.org calling for Ms. Pao to step down gained steam over the weekend and now has more than 200,000 signatures.

The moderators, who are considered crucial to the site’s success, were upset that the dismissal of a community liaison they relied upon left them unprepared to host already scheduled events. Ms. Pao apologized to users, posting Monday, “We screwed up.”