Francois Gendron, who serves as deputy premier and minister of agriculture, has represented Abitibi-Ouest for the Parti Quebecois since 1976.
His decision to run in an election that is expected to be called within weeks means he will be seeking an 11th consecutive mandate.
Gendron, who will turn 70 in November, was taken out of the legislature on a stretcher on Jan. 29 because of an illness.
When Gendron was elected for the first time, in the November 1976 election that brought Rene Levesque to power with the first PQ government, some of his current cabinet colleagues had not yet been born.
If Gendron is elected for an 11th time, he will beat the record of Liberal Gerard D. Levesque, who died in 1993 while serving as finance minister in the government of Robert Bourassa.
Gendron said Wednesday he is in good health after undergoing a battery of tests last week following his hospitalization a month ago.
"He's got some mileage but he's in good shape," Gendron quipped about himself, saying he had spent a few days considering his future.
Asked about his political longevity, he said he's not in politics to break records.
"I still have passion," he said. "I still have the will to serve."