Hicks first appeared professionally on stage at the age of sixteen in a production of "In the Ranks" at the Grand, Islington. In 1889, he joined the theatrical company of Mr. and Mrs. Kendal for an American tour where they presented a repertory of contemporary plays. Hicks starred as Dr. Watson in the first revue show ever staged in London, "Under the Clock" (1893), a parody of Sherlock Holmes and Watson written by Hicks with Charles Brookfield (who played Holmes), at the Royal Court Theatre. That same year, he married Ellaline Terriss. After that, he starred in a revival of "Little Jack Sheppard" at the Gaiety Theatre, London. This brought him to the attention of the impresario George Edwardes. In 1894, Hicks joined his wife in the successful "Fairy pantomime", "Cinderella", produced by Henry Irving with music by Oscar Barrett, where she had been playing the title role. He played Thisbe, one of Cinderella's half-sisters who, in this version, were "Girton College girls who can jabber Greek and Latin, read French, play golf, and indulge in manly exercises. Thisbe has an affectation for intellectuality – Ibsen, Spooks, and the new humor."