Engelbreit attributes her beginnings in art to getting eyeglasses in second grade and being able to see details of the world around her clearly for the first time. After meeting her first artist, at age 9, she became convinced she needed her own studio space, which her mother helped set up in the family linen closet.
Interested in art throughout her school years, the artist eventually began to work for a local advertising company, Hot Buttered Graphics. Hoping to work as an illustrator of children's books, she shopped her portfolio around New York City without success.
At the suggestion of one art director, she began working in greeting cards; her first nationally distributed greeting card featured a malapropism that played off the old saying, "Life is just a bowl of cherries," and showed a girl looking at a chair piled high with bowls, with the legend "Life is just a chair of bowlies." Engelbreit has been married to Phil Delano, a social worker, since 1977; in 1986 they formed their own company, presently called Mary Engelbreit Studios. The couple had two children, Evan, born 1980, and Will, born 1983. Evan passed away in June of 2000.
She has her own star on the St. Louis Walk of Fame.