On Broadway, Ellis played the roles of street urchin and errand girl in "Louis" in 1921, Nerissa in the 1922 production of "Merchant of Venice" and The Dancer from Milan in "Casanova" (1923). She gained wider notice by creating the title role in Rudolf Friml's long-running operetta "Rose-Marie" in 1924. She played Leah in The Neighborhood Playhouse's 1925 adaptation of "The Dybbuk", and her later Broadway roles included Anna in "The Crown Prince" (1927), Kate in a long-running revival of "The Taming of the Shrew" (1927–1928), The Baroness of Spangenburg "12,000" (1928) and Jennifer in "Meet the Prince". In 1929 she acted the title role in "Becky Sharp" in the Players' Club adaptation of "Vanity Fair", and played Laetitia in 1930 in "Children of Darkness".