Finance Minister Carlos Leitao had been holding onto the portfolio, doing double duty.
Moreau had stepped away last February due to a severe atypical multi-systemic infection.
“When I was sick, I was thinking about if ever I would resume my political career,” he said Monday.
“As soon as you feel well, the first idea that came to mind is doing what I like best in life and this is what I like.”
He was taken to the hospital from the National Assembly on the day he was set to be sworn in as education minister.
The MNA returned to work late last year as junior finance minister after his health improved following treatment.
Couillard said he is satisfied with bringing Moreau back, without making too many drastic changes.
“Quebec is better: more jobs, better economy, sound public accounts,” he said.
“So, there’s no evidence the direction taken by the government is not the right one. On the contrary.”
The 59-year-old represents the Montreal-area riding of Châteauguay and previously headed the municipal affairs and public security departments.
— With files from The Canadian Press