Leo Ernest Durocher, nicknamed "Leo the Lip" and "Lippy", was an American professional baseball player, manager and coach. He played in Major League Baseball as an infielder. Upon his retirement, he ranked fifth all-time among managers with 2,008 career victories, second only to John McGraw in National League history. Durocher still ranks twelfth in career wins by a manager. A controversial and outspoken character, Durocher's half-century in baseball was dogged by clashes with authority, the baseball commissioner, the press, and umpires; his 95 career ejections as a manager trailed only McGraw when he retired, and still ranks fourth on the all-time list. He won three National League pennants and one world championship.

In baseball, the field manager is the equivalent of a head coach who is responsible for overseeing and making final decisions on all aspects of on-field team strategy, lineup selection, training and instruction. Managers are typically assisted by a staff of assistant coaches whose responsibilities are specialized. Field managers are typically not involved in off-field personnel decisions or long-term club planning, responsibilities that are instead held by a team's general manager.