Member of the Mills Brothers singing group. He was the guitar (originally ukulele) player of the group. As the bass singer, he would imitate the tuba. Originally the brothers would perform in front of their father's barbershop after school singing while Harry played the kazoo. First named as Four Boys and a Kazoo. At their debut at the Mays Opera house in 1924, Harry forgot his kazoo and improvised a trumpet sound with his mouth and hands. Eventually, they became the first African-American group to have a major broadcast sponsor (Columbia). Their debut record, Tiger Rag/Nobody's Sweetheart, became the first million record sellers for a vocal group. Became the first African-American artists to give a command performance before British royalty in 1934, with their mother sitting in the royal box with King George V and Queen Mary.