Constellation Software president Mark Leonard resigns for health reasons

The CN Tower and Union Station are pictured in the financial district in Toronto, Friday, Sept. 8, 2023. THE CANADIAN PRESS/Andrew Lahodynskyj

TORONTO — Constellation Software Inc. says founder Mark Leonard has resigned as president of the company for health reasons, effective immediately.

The company says Mark Miller, who is currently chief operating officer, has been appointed president.

Leonard will remain as a director on the board, while Miller’s other roles within Constellation will remain unchanged.

Leonard says he and the board have complete confidence in Miller and the executive team.

He added that Miller has been a trusted adviser and a driving force within Constellation’s executive leadership team.

Leonard founded Constellation in 1995 after working in the venture capital business for 11 years.

This report by The Canadian Press was first published Sept. 25, 2025.