Mansur was born in Calcutta, India and moved to Toronto, Canada where he completed his doctorate studies in political science.
Mansur is a member of the Board of Directors for the Center for Islamic Pluralism based in Washington, D.C., a Senior Fellow with the Canadian Coalition for Democracies, a group which seeks to support democracies and placed particular emphasis on calling for the Canadian government to adopt a pro-Israel stance.
Salim Mansur was one of the founding members of Canadians Against Suicide Bombing, a group that has lobbied to amend Canada’s Criminal Code to cite suicide bombing as a terrorist crime, efforts which resulted in the passing of Bill S-215 on December 2010.
He is an academic-consultant with the Center for Security Policy in Washington, D.C. He has been a consultant with CIDA on development issues and has published widely in academic journals on foreign policy matters and area studies of the Middle East and South Asia.
He is featured on the documentary Obsession: Radical Islam's War Against the West produced by the David Horowitz Freedom Center. He also unsuccessfully ran for the Canadian Alliance party in 2000, being defeated by Sue Barnes.
Mansur, a Sunni Muslim, said he was ostracized after writing columns for the condemning the Taliban and comparing it to the Khmer Rouge of Cambodia. According to Mansur, the severe backlash has prompted him to stop going to his local mosque.
At a press conference on October 2, 2008, Mansur stated that "Islam is my private life, my conscience...[but] my faith does not take precedence over my duties...to Canada and its constitution, which I embrace freely;" "I am first and most importantly a Canadian;" "only in a free society will you find Islam as a faith and not a political religion." Mansur also criticized New Democratic Party Leader Jack Layton, whom Mansur said "has gone to bed with Islamists", because he is running candidates in Ontario and Quebec who are closely identified with the push for Sharia law