John Rumboldt is a founding member of a Tenant Agency brokerage firm located in Toronto, designed exclusively to meet the needs of commercial space users.

Over his 23 year career, his clients have included HSBC, DeBeers Canada, Royal Bank of Canada, National Bank of Canada, TD Canada Trust, Benjamin Moore, McDonald's Restaurants of Canada, Polo / Ralph Lauren, Registered Nurses Association of Ontario, Telus Mobility, Trafalgar Tours, The Ontario Opticians Association, and The Liquor Control Board of Ontario. In 2000 he was granted the designation of Broker. Commercial brokerage has remained his sole practice, where he has successfully completed over 300 commercial real estate transactions across Canada and around the world. These transactions include an assortment of commercial leases and sales.

During his career John has successfully handled transactions with many of Canada's oldest companies including all levels of government being Federal, Provincial and Municipal.

He has served twice as Vice President of the "CCIM" Central Canada Chapter, through the National Association of Realtors in Chicago, Illinois and currently resides in Toronto with his family.