Donn Trenner (born April 22, 1933) is an American jazz pianist, arranger, and music director, known for his contributions to the jazz and popular music genres. Trenner's career spans several decades, during which he has worked with prominent artists such as Frank Sinatra, Ella Fitzgerald, and Tony Bennett. He gained recognition for his innovative arrangements and skillful piano performances, particularly within the big band and swing styles. Notable works include his collaborations on albums and live performances, where his arrangements added depth and sophistication to the music. Trenner also served as the music director for various television shows, including the "The Merv Griffin Show," showcasing his versatility and adaptability in different musical contexts. Trenner's impact on music is reflected in his ability to blend traditional jazz with contemporary elements, influencing musicians and arrangers in the industry. His work has helped to bridge the gap between classic jazz and mainstream pop, making significant contributions to the evolution of American music. While not as widely known as some of his contemporaries, Trenner's artistry and professionalism have left a lasting mark on the music scene.