Born in New York City, Arnold started his career acting in summer stock and doing comedy in vaudeville.

"[3] Though his subsequent work was popular with audiences, Arnold frequently butted heads with TV executives regarding issues of content and fair shooting schedules.

Television sitcom writer-director Ken Levine described Arnold as "brilliant, unpredictable (a nice term for bi-polar), demanding, and kind.

[7] On August 28, 1986, Danny Arnold sold his production company Four D Productions, Inc. to Coca-Cola's Columbia Pictures Television Group for $50 million after Arnold dropped the federal and state lawsuits against Columbia Pictures Industries accusing them of antitrust violations, fraud, and breach of fiduciary duty.

[10] Arnold met his second wife, Donna, while he was working as a writer on The Tennessee Ernie Ford Show and she was appearing as a singer and dancer on the program.