Simma Holt (née Milner) was born March 27, 1922 in Vegreville, Alberta. She attended the University of Manitoba from 1941-1944, graduating with majors in English and Psychology.
During her time at the University, she was the first female managing editor of the student newspaper The Manitoban and was also a university reporter for the Winnipeg Free Press. Upon graduation in 1944, she began working as a teletype operator and reporter for the Canadian Press in Calgary. In the autumn of 1944, at age twenty-two, she began her thirty-year journalism career with the Vancouver Sun.

She married Leon Holt, a freelance photographer and later high school teacher in 1949. They were married for thirty-seven years, until his death in 1985.

In 1974, Simma Holt left the Vancouver Sun to successfully run as the Liberal member of Parliament for Vancouver-Kingsway. Holt was the first Jewish woman in Canadian history to be elected to Parliament. She sat for one term losing her seat in 1979. During her time in Parliament, she was Vice-Chair of the Standing Committee on Justice and a member of its subcommittee on the Penitentiary System. She was also a member of several Standing Committees: Broadcasting, Films and Assistance to the Arts; Privileges and Elections; Labour, Manpower and Immigration; National Resources and Public Works; Procedure and Organization; Transport and Communications; Finance, Trade and Economic Affairs; and Health, Welfare and Social Affairs.

In 1976, while still an MP, she became an occasional columnist for the Toronto Sun. Holt became a columnist for Ottawa Sun and Vancouver Business. She also was a freelance writer for Reader's Digest, Maclean’s, Fairlady in South Africa, Chatelaine and other magazines. Holt wrote four books: Terror in the Name of God: The Story of the Sons of Freedom (1965), Sex and the Teen Age Revolution (1967), The Devil's Butler (1971), The Other Mrs. Diefenbaker (1983), and Memoirs of a Loose Cannon (2008).

From 1981 to 1985, Holt was a member of the National Parole Board. She also acted as a researcher and writer in the presidential campaign of George Bush from 1987 to 1988, although later quit as she did not agree with Republican politics.

Holt was the recipient of numerous awards. In 1964 she was named Women of the Year for Canada in Arts and Letters for her book Terror in the Name of God. She was awarded, in 1969, the Jubilee Award by the University of Manitoba Alumni Association in recognition of her “distinguished achievement” in the 25 years since her graduation. The following year she won the Bowater Award of Merit in the sociological division for her series of articles on changing morality and sociological upheaval of teenagers. In 1985, she was a nominee for the Vancouver YWCA Women of Distinction award. She was inducted into the Canadian Newspaper Hall of Fame in 1996 and that same year she also was appointed a member of the Order of Canada. Her Order of Canada citation included the recognition that “she has demonstrated a lifetime commitment to assisting those suffering from injustice, persecution and poverty. Her perceptive and impassioned writings have contributed to positive social change by raising public awareness of injustices in society.” In 2002, she received a Queen Elizabeth II Golden Jubilee Medal for her contribution to public life.

Simma Holt passed away in Burnaby, BC on January 23, 2015.