Carl Reiner only wore a toupee for big crowds
He didn't mind being bald most of the time.
One of the things that made The Dick Van Dyke Show so resonant was its writing staff. The show's writers regularly drew from real-life occurrences, and that reality is reflected by the characters onscreen. Rob and Laura Petrie feel believable because so many of their stories and conflicts are based on things that actually happened to people. Genuine comedy veterans populate the rest of the cast, and so the laughs are all rooted in experience.
Take, for instance, The Dick Van Dyke Show's Carl Reiner. In addition to creating the series, Reiner starred as Alan Brady, Rob's boss and the host of a television variety show. The onscreen antics of the comedy writing staff feel realistic because of Reiner's experience writing comedy. Reiner cut his teeth writing for Sid Caesar's Your Show of Shows, and he based The Dick Van Dyke Show on that time in his life. So there was no shortage of credibility in the show's approach to depicting comedy writers.
Reiner drew from his real life in other ways, as well. In the episode "Coast to Coast Big Mouth," Laura Petrie reveals in an interview that Reiner's character Alan Brady wears a toupee.
"One of the best episodes we ever did," Reiner remarked in 2014. He went on to praise the episode's scribes, Sam Denoff and Bill Persky.
"They knew me," said Reiner, "and they knew I wasn't at all self-conscious about being bald: I only wear a toupee to feel dressed-up, or if there are more than 5,000 people present. But they knew Alan Brady didn't feel the same way."
He also praised Mary Tyler Moore's role in the episode.
"It was one of Mary's funniest performances," said Reiner. "She was a very quick study. It didn't take her very long."