Terriss performed from an early age, although she had no real ambition to act professionally. In 1887, she appeared in pantomime at the Alexandra Theatre, Liverpool. Petite, pretty and talented, she attracted the praise of both critics and the public. She came to the attention of Herbert Beerbohm Tree, who signed her to make her professional London debut in the role of Mary Herbert in "Cupid's Messenger", in 1888 at the Haymarket Theatre. Impressed by this performance, Charles Wyndham gave her a three-year contract, under which she first played Madge in "Why Women Weep". She also attracted the attention of a promising young actor, Seymour Hicks, and they married in 1893.