Garry Marshall, the noted producer and director, was talking about the best-known character in one of his best-known television shows.

“I always wanted a tall Italian boy,” he said in an oral history recorded in 2000 for the Television Academy. Instead it was a 5-foot-6-inch Jew named Henry Winkler who ended up playing the Fonz on “Happy Days,” a portrayal so distinctive that what had been envisioned as a supporting role became one of the most recognizable characters in television history.

The man responsible for that casting leap of faith was one of Mr. Marshall’s fellow executive producers on the series, Thomas L. Miller.

“Tom Miller was the whole key to casting Henry Winkler,” Mr. Marshall said in the oral history. Mr. Winkler, who was an unknown when he auditioned for the role in 1973, concurred.