CLEVELAND — Television is Donald J. Trump’s comfort zone, the medium where he ruled as master of “The Apprentice,” lured record audiences to Republican primary debates, and deftly outmaneuvered opponents with his camera-ready skills.

For politicos and producers alike, the Republican National Convention here this week was widely anticipated as a ratings bonanza.

It did not live up to the hype.

About 32 million Americans watched Mr. Trump’s climactic acceptance speech on Thursday evening on the major cable news and broadcast channels, according to ratings from Nielsen, released on Friday.

Mr. Trump’s remarks, at an hour and 15 minutes the longest in modern convention history, just beat out those of the previous Republican nominee, the decidedly less unpredictable Mitt Romney, who was seen by about 1.9 million fewer viewers when he addressed the party’s convention four years ago. Viewership throughout the convention week was about the same as in 2012.