WestJet chief executive Gregg Saretsky describes departing Cam Kenyon as a "skilled and valued leader" who exemplifies the airline's corporate culture.
Kenyon has been WestJet's executive vice-president of operations during a period when the airline has been preparing to launch its Encore regional service.
He joined the Calgary-based airline in January 2011 and will leave on July 20.
Kenyon says that commuting between his job and his home has been difficult since his family decided to return to Denver last June.
"I am regrettably leaving a company I love at a time when there are so many exciting initiatives underway," Kenyon said in a statement.
"This was a tremendously difficult decision that only I could make, but ultimately it is important that I put my own family ahead of my WestJet family."
WestJet is seeking a replacement.