In the 1990s, he developed learning materials for Apple Computer's eWorld online service, and produced the original Encarta Book of Quotations (1999) with Microsoft Inc. and Bloomsbury Publishing, London.
In the 1990s, he helped get Canada's SchoolNet under way, and developed the On This Day in Canadian History online service for Bell Globemedia.
He has done background research for Canadian authors such as W. L. Morton (research for a biography of Lord Strathcona), Peter C. Newman (Hudson's Bay Company series background history), Richard Gwyn (The 49th Paradox: Canada in North America), Pierre Berton (The Promised Land) and Jeffrey Simpson (Spoils of Power).
[citation needed] He is author of several books, including a biography of Sir George-Étienne Cartier (1976) and CanQuiz (2002).
Sweeny is currently executive director of the non-profit educational foundation The Civics Channel, dedicated to research, teaching and learning in the areas of citizenship and society, politics, human rights and the justice system.