The Citizens were initially frustrated by a resilient Bees outfit, who had their fair share of chances to break the deadlock, but the hosts' relentless pressure in the final third eventually told in the 71st minute when Haaland rounded off a swift counter-attack to slot a composed finish beyond Mark Flekken.
Haaland celebrated his first-ever goal against Brentford and has now found the net against all 21 teams he has faced in the Premier League since joining the Citizens in July 2022, becoming just the second player after former Tottenham Hotspur man Kane (32/32) to play against more than two clubs in the division and score against all of them.
Pep Guardiola's side held on for three important points to boost their Premier League title hopes and climb above Arsenal into second place in the table, one point behind leaders Liverpool who play host to Luton Town on Wednesday.
After losing 4-1 to Liverpool last weekend, Brentford were disciplined and well-organised in defence against Man City before Haaland eventually breached their backline, with the Norwegian condemning Thomas Frank's side to their ninth defeat in their last 11 top-flight matches, leaving them 14th in the table and five points above the drop zone.
Guardiola made three changes to the Man City lineup that began the 1-1 draw with Chelsea last weekend, with academy graduate Oscar Bobb handed his first Premier League start at the expense of Kevin De Bruyne, whose minutes continue to be managed having recently recovered from injury; John Stones and Bernardo Silva were also recalled as Nathan Ake and Jeremy Doku made way.
As for Brentford, Frank also made three alterations to the side that lost to Liverpool last time out, with Yoane Wissa, Frank Onyeka, Mathias Jorgensen all recalled - the former two handed their first starts since returning from the Africa Cup of Nations - at the expense of Neal Maupay, Nathan Collins and Mathias Jensen.
After failing to convert any of his nine attempts against Chelsea, Haaland looks like a man on a mission in the opening exchanges against Brentford; the Norwegian barged Sergio Reguilon off the ball before stinging the gloves of Bees shot-stopper Flekken with a strike from the edge of the area.
Phil Foden then forced another save from Flekken and dragged a second shot wide, before Haaland headed a half-chance over the crossbar.
Brentford responded well and had a few chances of their own at the other end; Stones was alert to deal with Ivan Toney's dangerous delivery into the box, before Ederson came off his line to get the better of Onyeka after the midfielder was slipped through on goal by Wissa.
The visitors were growing in confidence and came close again on the 20-minute mark when Toney fired a strike narrowly wide after receiving a short lay-off from a free kick.
Frustration grew among the Etihad faithful, with Guardiola seen on the touchline performing a few calm-down gestures to the home crowd, and although Man City turned the screw towards the end of the first half, Brentford had Flekken and Ben Mee to thank for keeping the scores level.
Indeed, the former made two crucial saves to deny both Manuel Akanji and Ruben Dias after Bernardo headed wide from just six yards out, before the balletic movement of Bobb allowed him to sidestep a challenge inside the area and fire goalwards, but Bees defender Mee anticipated the shot and got back brilliantly to clear the ball off the line.
Man City had 17 shots on goal in the first 45, but only five hit the target, while Brentford fired two of their five first-half shots on target, one of which was a decent header from Onyeka on the stroke of half time which was kept out by Ederson at full stretch.
An end-to-end start was made to the second half, with City initially camped in Brentford half, before the Bees broke on the counter-attack through Wissa and Onyeka, but the latter was unable to pick out the correct pass to a teammate and the chance went begging.
Frustrations continued to grow from the home supporters, as Brentford - particularly Flekken from goal kicks - squeezed every second out of dead-ball opportunity. Guardiola acted as cheerleader on the touchline to raise the Etihad volume, which then increased as Doku was called from the bench to replace Bobb on the hour mark.
Brentford's primary threat came from counter-attacks, but it was Man City's turn to burst from one end to the other and they were rewarded when Haaland netted the all-important opener in the 71st minute, much to the relief of the home crowd.
City's No.9 capitalised on Kristoffer Ajer slipping at a crucial moment to latch onto a through-ball from Julian Alvarez, before keeping his cool to stroke a shot beyond Flekken and settle the Etihad nerves.
Haaland momentarily thought he had double his and City's goal tally when he headed home from close range, but Kyle Walker was marginally ruled offside for his part in the build-up.
Brentford pushed for a late leveller in six minutes of stoppage time, but the Bees were unable to sting City's title hopes, and despite their best efforts to frustrate the Citizens, they remain in the relegation picture heading into the final third of the campaign.
Man City will endeavour to win back-to-back Premier League games when they travel to the Vitality Stadium to face Bournemouth on Saturday, two days before Brentford make the trip to the London Stadium to take on an under-pressure West Ham United outfit.