Formerly a law professor at Osgoode Hall Law School and a director of the Jack and Mae Nathanson Centre on Transnational Human Rights, Crime and Security,[3] he was elected as the New Democratic Party candidate in a federal by-election in Toronto—Danforth on March 19, 2012, following the death of Jack Layton in August 2011.

[5] From 1979 to 1981, he attended Lester B. Pearson United World College of the Pacific in Canada, where he gained the International Baccalaureate Diploma.

He was Osgoode Law School's Associate Dean (Research and Graduate Studies)[10] from 2001 to 2004 and has remained on the faculty subsequently.

Scott was an advisor to the African National Congress during its period in exile during the Apartheid era and subsequently assisted in the drafting of portions of the post-apartheid Constitution of South Africa.

[14] He won the seat on March 19, 2012, winning 59% of the vote, despite a strong campaign by second-place Liberal finisher, Grant Gordon.