Dwight Duncan says he's taking a job as a strategic adviser with the Toronto-based firm McMillan LLP.
The firm says the job involves helping clients invest in Canada and abroad.
Duncan announced last week he is quitting politics to make way for new blood in the Liberal front benches.
He is set to leave his Windsor-Tecumseh seat Thursday, which will force Premier Kathleen Wynne to call a byelection within six months.
Duncan, who oversaw the province's response to the recession, has admitted he won't miss being finance minister, especially when spending is severely limited by the $11.9 billion deficit.
In a statement released Wednesday, he says he looks forward to his new job, which starts next month.