City dominated the first half and deservedly took the lead after Haaland headed home from a pinpoint cross from Kevin De Bruyne in the 40th minute.
It was a matter of time until City got that crucial second goal, with Haaland converting from the spot following a foul on Ilkay Gundogan five minutes after the break. The Norwegian then quickly completed his treble to put the game to bed.
Haaland broke former Manchester United striker Ruud van Nistelrooy's record of being the fastest player to four Premier League hat-tricks. Haaland's four came in 19 games, Van Nistelrooy's in 65.
City cruised to victory from there on in to stay five points behind league leaders Arsenal, who beat Manchester United at the Emirates Stadium later on Sunday. Wolves stay 17th on 17 points.
"He (Haaland) has to get the balls delivered, he has fantastic players around him," coach Pep Guardiola said. "The ball from Kevin is fantastic.
"He (Haaland) lives 24 hours for his job, passion, and love. He's not stressed much. He is stable. He feels the defeats. His numbers are incredible.
"The way we played today was quite similar to the first half when we were losing 2-0 to Spurs (on Thursday). Our game, football was really good. Today we improved."
Haaland had in fact endured a mini-goal drought of three City appearances in all competitions prior to last week's strike against Tottenham Hotspur, but he certainly brought his shooting boots for the visit of struggling Wolves.
Haaland has more than double the league goals Wolves have mustered this season. They are only above the relegation zone on goal difference.
"We made mistakes, but the first half worried me more than the second half," coach Julen Lopetegui said.
"It's always possible to improve the squad while the (transfer) window is open, but it's important to improve the players who are already here."