Before entering politics, Brigdman was a police constable, a nurse, and a nurse administrator.
As a young woman, Bridgman lived and worked in London as a police constable (traffic bobby). Subsequently, she trained in London as a psychiatric nurse, becoming a Registered Nurse (RN) and a Psychiatric Nurse (PN) before returning to Canada. Bridgman went on to earn the Director of Nursing designation from the University of Saskatchewan, rising to become a nurse administrator.
In September 1993, the designated Reform Party candidate for Surrey North resigned his nomination. Bridgman was President of the Surrey North Reform Party Constituency Association, and she was selected to run as the Reform Party candidate. On October 25, 1993, Margaret Bridgman was elected the Member of Parliament for Surrey North, unseating the incumbent with a plurality of 6413 votes. Prior to Bridgman's landmark victory, Surrey North and its predecessor ridings had been held either by the New Democratic Party or the Progressive Conservative Party since 1958.
Bridgman served as the Reform Party Critic on Health and Assistant Critic on Indian Affairs and Northern Development. She sat as the Reform Party member of the House of Commons Standing Committees on Health and on Aboriginal Affairs and Northern Development, during the 35th Parliament. In her maiden speech in the House of Commons, Bridgman focused on the need for more effective and cost-conscious funding of health care in Canada. Bridgman's interventions in the House of Commons ranged from remarks on health care and Indian Affairs to young offenders, old age security, and the spending priorities of the Canadian parliament.
In 1997, Bridgman was successfully challenged for the Reform Party nomination by Chuck Cadman. Bridgman opted not to run as an independent in the 1997 general election, and she did not run, again, in a federal, electoral race.
Following the 1997 election, Bridgman returned to nursing in Surrey, British Columbia. After a sustained battle with lung cancer, Margaret Bridgman died at home on January 4, 2009.