The Mocambo opened on January 3, 1941. Along the walls were glass cages holding live cockatoos, macaws, seagulls, pigeons, and parrots. With big band music, the club became one of the most popular dance-till-dawn spots in town. On any given night, one might find the room filled with the leading men and women of the motion picture industry.
In 1943, when Frank Sinatra became a solo act, he made his Los Angeles debut at the Mocambo.
In the mid 1950s, Ella Fitzgerald became the first black performer at the Mocambo, after Marilyn Monroe lobbied the owner for the booking. The booking was instrumental in Fitzgerald's career. The incident was turned into a play by Bonnie Greer in 2005.
Ella Fitzgerald later said: "I owe Marilyn Monroe a real debt … she personally called the owner of the Mocambo, and told him she wanted me booked immediately, and if he would do it, she would take a front table every night. She told him – and it was true, due to Marilyn’s superstar status – that the press would go wild. The owner said yes, and Marilyn was there, front table, every night. The press went overboard. After that, I never had to play a small jazz club again. She was an unusual woman – a little ahead of her times. And she didn’t know it.”