Girling worked for
Suncor, Northridge Petroleum Marketing and
Dome Petroleum. Girling joined the TransCanada Corporation in 1994 and became its executive vice-president in 1995, subsequently creating the subsidiary TransCanada Power. In 2001 he became the president of TransCanada Gas Services. He subsequently served as the executive vice-president of corporate development and chief financial officer of TransCanada, until he became the president of pipelines of TransCanada Corporation. In this capacity, he oversaw gas and oil pipelines in
Canada, the
U.S. and
Mexico. He was later promoted to
chief operating officer. Girling serves on, and is chairman of, the board of directors of
Nutrien Limited He is the former chairman and chief executive officer of
TC PipeLines GP. In 2020, Girling announced he would be retiring from his position as the CEO of TC Energy. He spent 26 years at the company, 10 as the Chief Executive Officer. He was succeeded by François Poirier in January 2021. ==References==