"Mark has been a key leader on my team since the very beginning of my campaign in 2010," said Ford in a Wednesday release.
"He is a trusted advisor and well-respected in my office. He knows my objectives better than anyone and will help ensure we achieve them over the next two years."
Towhey succeeds Amir Remtulla, who stepped down just over a month ago to take a new job with the Toronto Pan and Parapan American Games.
Remtulla was widely praised by councillors and city hall insiders for his professionalism and his approachability.
Alan Slobodsky, who served as chief of staff and worked for 12 years under former mayor Mel Lastman, said in a July interview that Remtulla "accomplished a ton" during his time in the mayor’s office, including playing a role in reaching new labour deals with city workers.
Earl Provost, the mayor's director of stakeholder and council relations, was appointed interim chief of staff after Remtulla's departure. Provost will return to his prior role when Towhey starts his new job on Monday.
Towhey said he looks forward to taking on his new role and lauded the mayor for "an impressive list of accomplishments from his first 21 months in office."
"However, there is still a great deal to be done over the next two years. I look forward to working closely with Mayor Ford, his executive committee and city council to help them get that work done," he said in a statement.
Before joining Ford's mayoral campaign in 2010, Towhey was a management consultant working in Canada and the U.S., as well as "international organizations in conflict-affected areas worldwide," according to the release from the mayor's office. Towhey has an MBA from Western University's Richard Ivey School of Business.
He becomes the third person to serve as the mayor’s chief of staff since Ford was elected in the fall of 2010.
Nick Kouvalis held the position during Ford’s first few months in office.
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