After vocal studies with Alberto Randegger and Jenny Lind, and composition studies with teachers including Hamish MacCunn, Lehmann made her singing debut in 1885 in London and pursued a concert career for nearly a decade. In 1894, she married and left the stage. She then concentrated on composing music, becoming known for song cycles, art songs, parlour songs and children's songs. She also composed several pieces for the stage and wrote a textbook on singing. In 1910, she toured the United States, where she accompanied her own songs in recitals. She was the first president of the Society of Women Musicians and became a professor of singing at the Guildhall School of Music in 1913.