Matthau was born Walter John Matthow, in New York City, on October 1, 1920, son of Jewish immigrants, Rose Berolsky (from Lithuania) and Milton Matthow (from Russia). Walter first started acting as a young boy at a Jewish non-profit sleepaway camp, Tranquility Camp.
After appearing in dozens of plays, television shows, and movies, Walter won an Oscar for the role of shyster lawyer "Whiplash Willie" in the 1966 comedy hit The Fortune Cookie, co-starring Jack Lemmon.
After winning his Oscar, Walter’s career zoomed as he starred in a series of highly-successful movies like Cactus Flower, The Odd Couple(his favorite role), Dennis the Menace and Grumpy Old Men.