John Gladki's professional planning career began 38 years ago with the City of Toronto where he worked as a neighbourhood planner, district manager and director. As director of policy and strategic planning he completed the 1994 official plan which introduced urban design, social equity and environmental considerations as key policy objectives. In 1998 he joined the private sector as a director first with GHK Canada and currently with Gladki Planning Associates. Since then he managed projects such as planning for the revitalization of Regent Park, Canada's oldest and largest public housing complex, Growing Together, an analysis of growth patterns in the Greater Toronto Area (GTA) (a pre-curser to Ontario's Growth Plan for the Greater Golden Horseshoe), Waterfront Toronto's precinct plans, growth management studies for GTA municipalities, a climate change protocol for the CIP, revitalization strategies for public housing and development approvals. Throughout his career he has emphasized the need to incorporate affordable housing, inclusiveness and human rights as key planning considerations.

Early in his career he taught at Ryerson University and continues to lecture and speak in Canada and abroad. After the fall of the Soviet Union he worked with municipalities in Poland, Hungary, Lithuania, Latvia and Estonia to help with the transition to local democracy and more recently with municipalities in Bolivia and Palestine.