Hayden was born in Toronto as Mildred Herman and started her dancing career in Boris Volkoff's Canadian Ballet. After a brief stint at Radio City Music Hall, she danced with the American Ballet Theatre from 1945 to 1947. She joined the New York City Ballet shortly after its founding in 1948 by George Balanchine; she was a soloist with the company from 1953 to 1954 and a principal dancer from 1955 until her retirement in 1973.
She danced in numerous ballets, including Agon, The Figure in the Carpet and La Source. Balanchine created many works for her, including the 1958 Stars and Stripes. When Hayden announced her retirement, Balanchine created a ballet in her honor, Cortge Hongrois, which remains in the New York City Ballet's repertory. At the premiere performance of that work, she was presented with New York City's prestigious Handel Medallion by Mayor John Lindsay.
Hayden performed the ballerina role in Charlie Chaplin's movie Limelight and wrote two books, Melissa Hayden — Off Stage and On and Ballet Exercises.
After leaving the New York City Ballet, Hayden taught at the North Carolina School of the Arts from 1983 until a month ago. She also headed the ballet department at Skidmore College in Saratoga Springs, New York and was briefly artistic director of the School of Pacific Northwest Ballet in Seattle.
The New York Times described her style as "exultant, dramatic," writing that she was "direct in both her dancing and her views about dance ... [and] known for her unmatched blend of individuality and versatility."
The paper adds, "Anyone who saw her in Balanchine's step-packed Tchaikovsky ballet Allegro Brillante could be stunned by her outpouring of energetic classical style. At the close, Ms. Hayden seemed as emotionally spent as her audience."
She died at home in Winston-Salem, North Carolina of pancreatic cancer, according to the Times.