Kids are this episode's live studio audience.
The "new" dances Ralph plans to learn are The Big Apple, The Susie-Q, The Continental, and The Hesitation Waltz. All were years out of date by the 1950s. The first three peaked in popularity in the 1930s, and the Hesitation Waltz dates back to the ragtime era of the 1910s.
Jackie Gleason ad-libbed most of his closing monologue. The episode was running short and he had to stretch out his speech.
The title refers to the 1953 song "Young at Heart" written by Johnny Richards and Carolyn Leigh and made famous by Frank Sinatra.
The part of Judy's date Wallace was played by Ronnie Burns, the adopted son of comedians George Burns and Gracie Allen. Interesting fact: when Ralph tells Alice that Judy is "a 14 year old kid", Suzanne Miller (Judy Connors) was really 19 years old during filming, and Ronnie Burns (Wallace) who Judy tells Alice is "almost 18", was actually 20.