Lennie Niehaus was an influential American alto saxophonist, composer, and arranger, notable for his contributions to the West Coast jazz scene and his extensive work in film music. Born Leonard Niehaus on June 1, 1929, in St. Louis, Missouri, he grew up in a musical family; his father was a violinist who played in orchestras for silent films. Niehaus began his musical education on the violin before moving to the bassoon, and eventually settled on the alto saxophone and clarinet at age 13. He pursued formal music education at Los Angeles City College and Los Angeles State College, graduating in 1951.

Niehaus launched his professional career as an arranger and saxophonist with Phil Carreón and His Orchestra, and soon joined the Stan Kenton Orchestra, where he became a prominent lead alto saxophonist and staff arranger. His tenure with Kenton was briefly interrupted by military service in the United States Army from 1952 to 1954, during which he played in the 6th Infantry Division Band. Upon his discharge, he rejoined Kenton and continued to perform, compose, and arrange for the band until 1959.

Transitioning to a focus on composition, Niehaus became a respected figure in the world of film music. He began orchestrating for television and film in 1962, working with composer Jerry Fielding. His most notable collaboration was with Clint Eastwood, a partnership that began due to their shared love of jazz during their Army days. Niehaus scored numerous Eastwood films, including "Pale Rider," "Heartbreak Ridge," "Unforgiven," and "The Bridges of Madison County." Their most acclaimed collaboration was the biographical film "Bird," about jazz saxophonist Charlie Parker, which won awards for its innovative soundtrack.

Throughout his career, Niehaus maintained a connection to jazz, releasing albums like "Lennie Niehaus, Vol. 1: The Quintets" and "Sunday Afternoons at The Lighthouse." He passed away on May 28, 2020, in Redlands, California, leaving behind a legacy that bridged the worlds of jazz performance and film composition.