Hayes had her first child, a daughter Nan (born 1937), from her brief first marriage to Charles DeBuskey. The couple divorced in 1939, and Hayes subsequently married actor Leif Erickson on June 12, 1942, eloping with him to Minden, Nevada. They separated 28 days later, and Hayes received a divorce on October 2, 1942.
After marrying Herbert Bayard Swope in 1946, Hayes temporarily retired from acting and turned to journalism, eventually becoming assistant fashion Editor for Life magazine.
Hayes was often billed as Maggie Hayes in her film credits. She is perhaps best known for her role as Lois Judby Hammond in the 1955 film Blackboard Jungle, which starred Glenn Ford. In 1956, she guest-starred as Dora Hand in three episodes of The Life and Legend of Wyatt Earp. She appeared in the episode "The San Saba Incident" (October 18, 1957) of Trackdown, playing a female convict, named Abby Lindon.
Hayes' films included The Glass Key, Sullivan's Travels and Good Day for a Hanging. In 1958, in the film Damn Citizen, Hayes appeared opposite Keith Andes in the role of a real person, Dorothy Maguire Grevemberg, the wife of the crusading Louisiana State Police superintendent Francis Grevemberg. She made four guest appearances on CBS's Perry Mason. In 1961, she portrayed the part of Mrs. North in the episode "Incident of the Night on the Town" on CBS"s Rawhide.
Hayes died January 25, 1977, aged 60, in Mount Sinai Medical Center & Miami Heart Institute in Miami Beach, Florida from liver cancer and hepatitis.