Called to the Bar of Ontario in 1966, lawyer and judge Sidney Linden was in private practice until 1980. Between 1980 and 1985, he was the first Police Complaints commissioner for metropolitan Toronto and chair of the Police Complaints Board. Between 1985 and 1987, he was director of the Canadian Auto Workers Prepaid Legal Services Plan, the first privately funded national prepaid legal service plan in Canada. In 1987, he was appointed Ontario's first Information and Privacy commissioner.
In April 1990, he was appointed Chief Justice of the newly reorganized Ontario Court of Justice (provincial division). During that time, he was co-chair of the Ontario Judicial Council and a member of the board of the National Judicial Institute. Linden has also served as chair of the board of Legal Aid Ontario from 1999 to 2004, and as commissioner of the Ipperwash Public Inquiry from 2004 to 2007.
Legal Aid Ontario created the Sidney B. Linden Award, named after their first chair of the board of directors, to honour exceptional individuals who have demonstrated a commitment to helping low-income people, and who have given their time and expertise towards ensuring access to justice in Ontario. Linden was also recognized by the Canadian Institute for the Administration of Justice with a Justice Award. In 2009, he was awarded an honorary doctor of laws by the Law Society of Upper Canada.