Liberal Premier Brian Gallant said Shelley Rinehart will be the party's candidate in Saint John East.
Rinehart teaches marketing in the faculty of business at the University of New Brunswick in Saint John.
"I've never belonged to a political party before," Rinehart said in a statement. "But I love my community. I have long had a passion for public service and I'm very excited to ask Saint Johners for the privilege to take that service to the next level."
Gallant said Rinehart has critical experience in economic and energy issues.
"Our government's focus is job creation and a big part of that is centred in Saint John," he said.
Gallant has called the byelection for Nov. 17.
The seat became vacant last week after Liberal Gary Keating quit politics, saying the hours and travel that come with the job would have a negative impact on his health and family.
The Opposition Progressive Conservatives have said Glen Savoie, who narrowly lost to Keating in last month's provincial election, will get the nod as their candidate.
Members of the New Democratic Party have launched an effort to convince their leader, Dominic Cardy, to run in the riding.