Diamond was born in London, Ontario, Canada in 1920 to a tailor and his wife, but moved at a young age to Brooklyn, New York. She was graduated from New York University and published cartoons and humour essays in The New Yorker before moving to the West Coast, hiring an agent, and finding work in radio and, eventually, television. Her first radio writing credit was in 1943 on Pabst Blue Ribbon Time with Groucho Marx, the Camel Caravan with Jimmy Durante and Garry Moore, The Drene Show with Rudy Vallee, Duffy's Tavern, and The Kenny Baker Show. In 1950, she became one of the staffers hired by legendary comedy Writer Goodman Ace (who'd previously hired her for some work on Danny Kaye's short-lived 1940s' radio show) for The Big Show (1950–52), the ninety-minute weekly program hosted by Actress Tallulah Bankhead. Considered one of the last great variety shows of the classic old time radio era, this Sunday night comedy marathon featured some of the biggest entertainers of the era.