Born in Chicago, Illinois, Kostal attended Harrison Technical High School,[1] but opted not to attend college, instead teaching himself musical arranging by studying the symphonic scores available at his local library. His first professional job was as a staff arranger for Design for Listening, an NBCradio show based in his hometown. Irwin was one of four children born to James and Emma Kostal in a Czech enclave of Chicago.[2] His siblings James, Jerome and Violet all remained in the Chicago area.[3]
In the late 1950's he arranged and conducted two of Julie Andrews early solo albums on RCA records, "The Lass with the Delicate Air" and "Julie Andrews Sings".
For the remainder of his life, Kostal divided his time primarily between stage and screen, with an occasional detour into television to work with such people as Carol Burnett, Lucille Ball, and Leonard Bernstein. He supervised five of the Sherman Brothers musical film scores (one of them being Mary Poppins) at four different movie studios between 1964 and 1978. In 1982, he conducted the digital re-recording of the music to Walt Disney's 1940animated featureFantasia.
1954-56 Max Liebman's NBC Spectulars: The Merry Widow, Tales of Hoffmann, The Gypsy Baron, Der Fledermaus, The Desert Song with Nelson Eddy, Babes in Toyland, Naughty Marietta, Marco Polo and Lady in the Dark. Orchestrator