Harper was born in 1899 in Birmingham, Alabama, to William Harper, a performer, and his wife. Harper started dancing as a child to attract a crowd on a medicine show wagon, traveling with the show throughout the South. In 1915, he first toured in New York City, and quickly moved to Chicago.
There he began choreographing and performing dance acts with Osceola Blanks of the Blanks Sisters, who became the first black act for the Shubert Brothers.[9]
Harper and Osceola Blanks performed in his first big revue, Plantation Days, when it opened at the Lafayette Theatre in Harlem in 1922–23.[11] He began producing floor shows in Harlem and New York thereafter.
From 1923 to 1924, Harper offered the Duke Ellington Orchestra the house band position at the speakeasies Connie's Inn in Harlem and the Kentucky Club in Times Square. He was producing shows there and the Duke Ellington orchestra played as the house band at the Kentucky Club for the next four years. At the suggestion of drummer Sonny Greer, Ellington and his wife Edna, along with their son Mercer Ellington, stayed in one of Harper's Harlem apartment bedrooms in the early 1920s.[12]
Harper was part of the transition team when the Deluxe Cabaret was turned into the Cotton Club, producing two of its first revues during its opening. His biggest milestone on the Great White Way was his staging of the Broadway hit Hot Chocolates, which established the classic Broadway show tunes "Black and Blue" and "Ain't Misbehavin'". Harper was one of the leading figures who transformed Harlem into a cultural center during the 1920s. His nightclub productions took place at Connie's Inn, the Lafayette Theatre, the new Apollo Theatre, and other theatres in New York.
He had a daughter, Jean Harper, out of wedlock with Fannie Pennington.
The late Leonard Harper is one of this year's 2022 inductees into the ATDF Tap Dance Hall of Fame, the only Tap Dance Hall of Fame focused exclusively on 20th and 21st century professional tap dancers.