Templeton was the daughter of theatrical parents—principals in the touring John Templeton Opera Company—and grew up entirely in that milieu. She was carried onstage in infancy and had her first speaking part at age five.

By the early 1880s Templeton was touring the country with her own light opera company. Her ascent to fame began with her appearance in Evangeline in New York City in 1885. She made her London debut the following year in Monte Cristo, Junior. In a succession of extravaganzas over the next decade, she became celebrated equally for her singing, her acting, and her dark, seductive beauty. She appeared with the team of Joe Weber and Lew Fields (Weber and Fields) in their burlesque Hurly Burly (1898), in which her talents for comedy and parody were realized. She starred in Weber and Fields's Fiddle-dee-dee (1900), Hoity Toity (1901), and Twirly Whirly (1902), all of which also featured Lillian Russell (Russell, Lillian). In 1906 Templeton starred in George M. Cohan (Cohan, George M.)'s Forty-five Minutes from Broadway, in which she introduced “Mary's a Grand Old Name” and “So Long, Mary.”

For a quarter-century thereafter, Templeton lived in semiretirement with her husband in Pittsburgh, Pennsylvania, emerging to appear in such productions as Weber and Fields's Hokey Pokey in 1912 and several versions of H.M.S. Pinafore. She appeared in the film Broadway to Hollywood (1933) and late in 1933 returned to Broadway in Jerome Kern (Kern, Jerome)'s Roberta.