Merle Louise Simon, a Sondheim Mainstay, Is Dead at 90

Merle Louise Simon, an award-winning stage actor and the only person to play roles in the original Broadway productions of four Stephen Sondheim musicals, died on Jan. 11 in Lake Katrine, N.Y., in Ulster County. She was 90.

Her daughter Laura Simon confirmed the death, in a nursing home.

Ms. Simon — who worked for most of her career under the name Merle Louise — began her run in Sondheim shows with “Gypsy,” in 1959, and continued with “Company” (1970), “Sweeney Todd: The Demon Barber of Fleet Street” (1979) and “Into the Woods” (1987), Mr. Sondheim and James Lapine’s interpretation of fairy tales. (Mr. Sondheim wrote the lyrics for “Gypsy” and the music and lyrics for the other shows.)

“Steve had a real history with Merle,” Mr. Lapine, who directed Ms. Simon in three roles, including the Giant in “Into the Woods,” said in an email. Mr. Sondheim, he added, “loved the energy she brought to the rehearsal room and the stage. Merle was usually the smallest person in the room but always the most ebullient and with the most glorious voice.”

When “Gypsy” opened, Ms. Simon had a minor role. But she was promoted in early 1960 to be the understudy to the actress playing June, one of two daughters pushed into show business by their ambitious mother, Rose, played by the powerhouse Ethel Merman.

Soon after becoming the understudy, Ms. Simon went on for the actress in the role, who was ailing, and ended up becoming the full-time June.