Over six decades, Ms. Kobart played musical comedy roles, movies and TV, the classics and opera throughout the country and internationally. A Des Moines, IA, native, she pursued a career in opera in New York City after studying at the American Conservatory of Music in Chicago. She made her professional debut Off Broadway as the Witch in Hansel and Gretel with the Lemonade Opera (an experimental cooperative group to which each member donated $25 to generate productions) and then frequently performed in New York and on tour with NBC Opera (Macbeth, The Marriage of Figaro, Gianni Schicchi) and New York City Opera (The Ballad of Baby Doe, The Old Maid and the Thief, Susannah, The Rape of Lucretia, Street Scene, The Mikado, Six Characters in Search of an Author and The Inspector General, the last two directed by Bill Ball, who founded A.C.T. a decade later). She created the role of the maid Agata in Giancarlo Menotti's Maria Golovin, which got its world premiere at the United States Pavilion at the 1958 Brussels World's Fair, and reprised her performance in the American premiere production on Broadway, produced by David Merrick.
Prior to that short-lived production (it lasted five performances), Kobart had made her Broadway debut in the chorus and understudied Helen Traubel in the lead of Rodgers and Hammerstein's 1955 Pipe Dream, playing the role 20 times.
In 1961 she played the executive assistant Miss Jones (a role she repeated in the movie), in which she belted out a high note during the Frank Loesser "Brotherhood of Man" number. She stayed with the entire run of Forum in 1963, taking short leaves to tour with New York City opera.
In the 1967 inaugural season at A.C.T., she played Madame Pernelle in Tartuffe, the company's first production at the Geary Theater. Over the following three decades her A.C.T. productions included The House of Bernarda Alba, Hotel Paradiso, Sunday in the Park with George, Saturday, Sunday and Monday, Broadway, The Torchbearers, Arsenic and Old Lace, Thieves' Carnival, The American Dream, Hotel Paradiso, When We Are Married, A Funny Thing Happened on the Way to the Forum and Home, her final company production, directed in 1994 by A.C.T. artistic director Carey Perloff. "Working with Ruth was such a joy," Perloff said in a statement. "She had more comedy in her little finger than most people have in toto, and pathos as well. She was a star in her own right, but also a consummate company member. She just adored the theatre."
In the 1970s, while on leave from A.C.T., Ms. Kobart spent 18 months portraying Nurse Ratched in the long-running San Francisco production of One Flew over the Cuckoo's Nest. She also toured nationally in the comedies Forty Carats, Boeing, Boeing, The Last of the Red Hot Lovers and was the Miss Hannigan in the first national tour of Annie.
