He served in the Legislative Assembly of Ontario from 1977 to 1985 as a member of the Progressive Conservative Party, and was briefly a cabinet minister in the government of Frank Miller.
After the leadership convention, Miller appointed Rotenberg to cabinet as a minister without portfolio responsible for Urban Affairs.
[5] Near the end of his tenure as premier, Bill Davis announced that he would extend full funding to the province's Catholic school system.
Rotenberg later said that Garnsworthy's comments created a climate of religious intolerance in the province, and took support away from the Progressive Conservative Party.
A decade later, Rotenberg attempted a return to politics and campaigned for the House of Commons of Canada in the 1997 federal election as a candidate of the Progressive Conservatives in the riding of Eglinton—Lawrence.
[7] The Canadian Alliance tried to recruit Rotenberg as a candidate in Willowdale for the 2000 federal election, but he was disqualified because he had not been a party member for long enough.