The daughter of Irish restaurant owner Luke Joseph Higgins and Nora C. (Durkin) Higgins, Mary Higgins grew up in the Bronx and attended Villa Maria Academy and Ward Secretarial School. She wrote her first poem at seven and frightened friends with scary ghost stories. The sudden deaths of her father and her older brother Joe affected her deeply. At seventeen she became a Remington Rand advertising assistant. Creative writing classes at New York University inspired her to join a writing group that became the Adams Round Table and eventually led to five short-story collections. While working as a Pan Am flight attendant (1949-1950), she married long-time friend and airline executive Warren F. Clark. When her husband died in 1964, Clark was left with five children to support. She wrote and produced radio scripts for Robert G. Jennings (1965-1970) while writing in her free time. When her first published book, Aspire to the Heavens: A Biography of George Washington (1969), proved a commercial failure, she turned to the mystery genre. In 1970 she went to work for Aerial Communications, where she served ten years as vice president, partner, and radio programming creative director/producer.

Clark’s publication of Where Are the Children? (1975) earned more than $100,000 in paperback royalties and marked the beginning of her long, successful second career as a mystery writer attuned to childhood fears, mother-child relationships, the traumatic loss of family members, and the spine-tingling fears of women alone in the dark. In 1978 she married attorney Raymond Charles Ploetz and moved to his Minnesota farm but soon had the marriage annulled. She received a bachelor’s degree in philosophy from Fordham University, graduating summa cum laude in 1979. In 1980 she became chair of the board and creative director of David J. Clark Enterprises in New York. Not until her second thriller, A Stranger Is Watching (1977), earned a $500,000 advance, more than $1 million in paperback rights, and film rights from Metro-Goldwyn-Mayer did Clark feel she had the financial security she needed to leave Aerial and raise her family in comfort. In 1989 she signed a then-record-breaking $11.4 million contract with Simon & Schuster and in 1992 a $35 million contract.

Clark served as president of the Mystery Writers of America in 1987 and has since served on the board of directors. As chair of the International Crime Writers Congress, she attended a Federal Bureau of Investigation lecture on serial killers using personal ads to entice victims, which became the inspiration for Loves Music, Loves to Dance (1991). Her literary interests have led her to join various authors’ guilds and academies, including the American Irish Historical Society. In 1996 Clark established the Mary Higgins Clark Mystery Magazine, which publishes mystery and suspense stories.

In 1996, she married retired chief executive officer John J. Conheeney, whose name she uses in her private life. Their renovated home in Spring Lake, New Jersey, became the setting of On the Street Where You Live (2001). Clark continues to write novels, sometimes with her daughter Carol Higgins Clark, with whom she revived the Alvirah and Willy Mehan series by creating several Christmas-themed novels. Clark contributes regularly to periodicals on a wide variety of topics. More than twelve of her works have been filmed.

With more than fifty million books in print, Clark enjoys best-seller status worldwide. Her many awards include the New Jersey Author Award in 1969 for Aspire to the Heavens, the Grand Prix de Littérature Policière in 1980 for A Stranger Is Waiting, thirteen honorary doctorates, and the titles of dame of the Order of St. Gregory the Great, dame of Malta, and dame of the Holy Sepulcher of Jerusalem. In 2000 she was named Grand Master by the Mystery Writers of America.