Furnish graduated from the Sir John A. Macdonald Collegiate Institute in 1981 and received an Honours Business Administration undergraduate degree from the Richard Ivey School of Business at the University of Western Ontario in London, Ontario in 1985.
He is the husband of British singer Elton John. He has an older brother, John, and a younger brother, Peter. He was recruited by the advertising agency Ogilvy & Mather, eventually transferred to the London, England, office and was appointed to their Board.
Furnish is co-chief of Rocket Pictures along with John.
Furnish serves on the board of the Elton John Acquired Immune Deficiency Syndrome Foundation, attending fundraisers and other events in support of that cause. Furnish is a contributing editor for Tatler magazine and also is a regular columnist for Interview and Gentlemen’s Quarterly. Furnish began a relationship with singer Elton John in 1993.
John proposed to Furnish in May 2005 at a dinner party with friends and family at one of their homes in Old Windsor. Furnish and John entered into a civil partnership on 21 December 2005, the first day that civil partnerships could be performed in England, in the town of Windsor, Berkshire.
Their first child, son Zachary Jackson Levon Furnish-John, was born in December 2010 in California via surrogacy.
In January 2013, the couple"s second son, Elijah Joseph Daniel Furnish-John, was born through the same surrogate. In 2015, he was named one of Gentlemen’s Quarterly"s 50 best dressed British mentor