Made as a tribute to Billy Wilder, one of the filmmaker's favorite directors.
Every character was named for an actor that worked with Billy Wilder: Jack (Lemmon), Barbara (Stanwyck), and William (Holden).
Jack's line "...all wrapped in tissue paper, with pink ribbons around it. Perfect, except that it wasn't" was borrowed from the opening monologue of Billy Wilder's Double Indemnity.
Various production design elements were meant to echo the 1920s Art Deco style in order to signal the age difference between Jack and Barbara. They live in Los Feliz Manor, a Los Angeles building constructed in 1929 as a calling card of the glamorous Art Deco era. The compact mirror Jack gives his wife as an anniversary gift also has a distinctly Art Deco design.
The director's maternal grandfather was the inspiration for making Will and Barbara originally from Poland. As a young child in the early 1900s, he had emigrated with his family to the US from Poland.