The cause of death was cancer, according to The New York Times. She was 76. For many fans of the hit musical take on Cervantes' "Don Quixote," Ms. Diener was and will forever be the voice of Aldonza, the kitchen wench elevated to the status of Lady by the addled title knight.
On the popular original cast album, Ms. Diener sings in chest and head voices, and the two qualities suggested an inner struggle — a fight for the soul of the woman. She was of both heaven and earth.
The Mitch Leigh-Joe Darion song "Aldonza" remains a frank, blistering tirade of self-recognition and self-abnegation in which angry, broken Aldonza refutes any elevated labels other than "kitchen slut" and "whore." Ms. Diener spat out that she was "spawned in a ditch" and "born on a dung heap — to die on a dung heap."
The effect was rich in character, but not necessarily gorgeous. "Joan Diener's performance is a puzzle," wrote Times critic John S. Wilson, reviewing the cast album 40 years ago. "She has plenty of voice when she chooses to open up in operatic style. Most of the time, however, she uses a rather flat, colorless manner of singing."
Ms. Diener, a blonde who made brunette for the role of Aldonza, would play the role in revivals for many years. As late as 1992 she stepped into the part on Broadway, replacing Sheena Easton. Ms. Diener's husband, Albert Marre, directed the original Broadway staging in 1965. He survives. For a 1968-69 production of the musical in Brussels and Paris, Ms. Diener sang the role in French opposite Jacques Brel. The French adaptation (book and lyrics) was by Brel. The 1968 French cast recording of L'homme de La Mancha has recently been re-released on the DRG label.
Ms. Diener won a Theatre World Award in 1954 for her work in Kismet. She played the buxom Lalume, another lusty role.
Her Broadway credits also included the musical Home Sweet Homer (1976), the 1972 revival of Man of La Mancha, the musical Cry for Us All (1970), the 1950 play Season in the Sun, and the 1948 musical revue Small Wonder.
Of her work in Kismet, set in an idealized, glamorous Baghdad, Brooks Atkinson of the Times wrote, "As an abandoned hussy, brazenly made up and loosely clad, Joan Diener looks like a fine case of grand arson."
She also worked in nightclubs (Blue Angel), early TV ("Adrocles and the Lion" on "Omnibus" in 1956), regional theatre (Destry Rides Again at North Shore Music Theatre) and in pre-Broadway shows such as At the Grand and The Ziegfeld Follies of 1956 (they never made it to Broadway).
Ms. Diener was born in Columbus, Ohio, on Feb. 24, 1930, and attended Sarah Lawrence College in Bronxville, NY. She was a psychology major and part-time actress.
In addition to Albert Marre, survivors include daughter Jennifer Marre, son Adam Marre, and three grandsons, all of Brooklyn.