As an opera singer, Harrold specialized in the lyric tenor repertoire of the Italian and French languages. In 1911–1912 he performed with Hammerstein's opera house in London. From 1912–1922 he was one of the leading opera tenors in Chicago; performing with a variety of companies in that city. He spent the last 6 years of his opera career performing at the Metropolitan Opera in New York City; giving his last opera performance there in 1924. He continued to perform in vaudeville entertainments up into the late 1920s. He made several gramophone records during his career; including recordings for Edison Records, Columbia Records (1913–1916) and the Victor Talking Machine Company (1920–1924).