Isaac Sidney "Sid" Caesar (born September 8, 1922) is an American comic actor and writer known as the leading man on the 1950s television series Your Show of Shows and Caesar's Hour, and to younger generations as Coach Calhoun in Grease and Grease 2.

Caesar was born in Yonkers, New York, the son of Jewish immigrants Ida (née Raphael) and Max Caesar, who ran a twenty-four-hour luncheonette. Caesar would help his parents by waiting on tables and it was during this time that Sid learned to mimic many of the accents he would use throughout his long career. He first tried his double-talk with a group of Italians, his head barely reaching above the table. They enjoyed it so much, they sent him over to a group of Poles to repeat it in Polish, and so on with Russians, Hungarians, Frenchmen, Spaniards, Lithuanians, and Bulgarians. Despite his apparent fluency in many languages, in reality Caesar can only speak English and Yiddish. The Caesars were a funny family, and Sid's older brother Dave was his comic mentor and 'one-man cheering section'. They created their earliest family sketches from then current movies like Test Pilot and Wings.

At fourteen, Caesar first went to the Catskills as a saxophonist with Mike Cifficello's Swingtime Six and would also occasionally perform in sketches. After graduating from high school in 1939, Caesar's family was still reeling from the Great Depression, and he moved out, intent on a musical career. He arrived in New York City penniless and tried to join the musician's union (later he audited classes at the famed Juilliard School of Music). That first summer on his own, he played at the Vacationland Hotel in Swan Lake in the Catskills. There under the tutelage of Don Appel, the resort's social director, Caesar played in the band and learned to perform comedy, doing three shows a week. In 1939, he enlisted in the United States Coast Guard, where he was assigned to play in military revues and shows in Brooklyn, New York. Vernon Duke, the famous composer of Autumn in New York, April in Paris, and Taking a Chance on Love, was also stationed at the same base and he collaborated with Caesar in musical revues.