Having already guaranteed a match ball by the half-time whistle, Haaland added a further two strikes before the hour mark to take his tally to 39 for the season - becoming Man City's highest goalscorer ever in a single campaign.
Ilkay Gundogan and Kevin De Bruyne also got in on the act as the Premier League champions dismantled their beleaguered opponents, who were a shadow of the team that deservedly drew with City just three weeks ago.
While both sides were willing to press aggressively from the off, Pep Guardiola's charges soon began to dominate possession, and it took just 11 minutes for Haaland to have his first sight of goal.
Latching onto a long ball over the top from Nathan Ake, Haaland burst past Josko Gvardiol with ease but could not poke the ball past the onrushing Janis Blaswich.
Just 11 minutes later, the latest controversial interpretation of the handball rule came into play, as Rodri's header from a corner brushed the outstretched arm of Benjamin Henrichs on its way down.
Leipzig survived the ensuing goalmouth scramble, but referee Slavko Vincic was advised to look at the monitor, and the Slovenian barely hesitated before awarding a spot kick for Henrichs's handball.
The right-back was booked in the process as Haaland crashed a penalty into the bottom corner to give the hosts the lead on the night and on aggregate - Blaswich went the right way but was powerless to prevent the Norwegian opening his account.
A similar theme would follow as the first half progressed, and the ball was in the back of the net for a second time just 19 seconds after the restart, as De Bruyne crashed a 20-yard effort off the bar before Haaland leapt to head home the rebound.
The 22-year-old's header made it 30 goals in 25 Champions League games for the Nordic trailblazer - unsurprisingly the quickest time to hit that landmark - and he was denied a hat-trick in the 31st minute by Blaswich at his near post.
While the Leipzig number one was seeing most of the action, City number one Ederson clattered into Konrad Laimer with a raised boot in the 34th minute - the Brazilian's foot missed the Leipzig man, but he left plenty on him well outside his area.
However, the only card brandished during the incident saw Timo Werner booked for his protests, as Ederson got off scot-free before witnessing Haaland bring up a terrific treble in the second minute of added time.
Ruben Dias met a corner at the back stick, and the centre-back's header hit the inside of the post and trickled across the line - Amadou Haidara reacted quickest and attempted to clear, but he only succeeded in hitting the ball off Haaland's leg as the striker brought up his fifth hat-trick of the season.
Any choice words that Marco Rose had for his side at half time had little to no effect, as Gundogan fired in the hosts' fourth on the 49-minute mark, cutting onto his left and finding the far corner from just inside the box following a smart link-up with Jack Grealish.
The Haaland-inflicted humiliation would only get worse for a disjointed Leipzig just four minutes later, as despite Blaswich's best efforts in a goalmouth scramble - keeping out Haaland's header and Manuel Akanji's follow-up - the former was in the right place at the right time to fire home number four on the half-volley.
Clearly not learning their lessons from the last set-piece, Leipzig became victims of a five-star Haaland showing in the 57th minute, as Blaswich palmed the ball into the Scandinavian's path, and he duly obliged - firing home into the far corner for a scarcely believable fifth.
The one-man onslaught would soon end, as Guardiola offered Leipzig a slice of mercy by bringing Haaland off in the 63rd minute, having seen the Norwegian become just the third player to score five goals in a single Champions League game after Luiz Adriano and Lionel Messi.
As the action died down in the final half-hour, there was time for De Bruyne to get the goal his performance warranted in added time, curling home a sublime effort into the top corner from outside the area.
An FA Cup quarter-final against Vincent Kompany's Burnley is next up for Man City on Saturday, while Marco Rose's Leipzig have an identical recovery period before returning to Bundesliga action away to VfL Bochum.