Cadorette was born in East Hartford, Connecticut. She started taking dance classes when she was five years old and later entered dance competitions. She gives credit to her love of dance for her career milestones. She was Miss Connecticut in the 1975 Miss America pageant. She graduated from the University of Connecticut in 1979, after which she performed in dinner theatres and with the USO. She also spent three and a half years on Broadway as an understudy in the musical 42nd Street. In 1990, she landed the recurring role of Margaret Turner on Night Court. She owned her own restaurant in Los Angeles in the 1990s, Mary's Lamb, that was frequented by many celebrities.
Mary has been in a few films, Stewardess School, and The Rat Pack among them. During the 1980s, she was also seen on a number of game shows, including The $25,000 Pyramid, Super Password, and Body Language.
In 1999, she left California and moved back home to Connecticut to take care of her mother who had suffered a stroke. Her mother died eight years later. She and two friends, whom she had known since they were in dance school as children, decided to take up dancing again after many years. They formed the "The Chapeau Rouge Dance Project" encouraging former (and older) dance students to attend classes in the dance studio that they have rented.
She was married to Michael Eisen in 1982. Soon after, she married William Harris and now goes by the name Mary Cadorette-Harris.
In March 2011, she directed and choreographed Hairspray at Glastonbury High School in Glastonbury, CT.
She now teaches at Greater Hartford Academy of the Arts Tap and Ensemble Class in Hartford, CT.