City entered the clash at the Amex one point clear of second-placed Liverpool, knowing that a victory over the Seagulls would see them become the first side to retain the Premier League title for 10 years.
Liverpool kept to their end of the bargain by beating Wolverhampton Wanderers at Anfield to move onto 97 points for the campaign, but City's success saw them end on 98 points at the conclusion of a stunning title race.
Brighton entered the match having not beaten City in the league since 1989 - Liverpool were looking for a huge favour from Chris Hughton's team, but it never looked like a possible outcome despite the home side taking the lead.
City's team showed one change from the win over Leicester City on Monday night, with Riyad Mahrez coming in for Phil Foden. Kevin De Bruyne was deemed fit enough for a spot on the bench, but Fernandinho once again missed out due to a knee problem.
Mahrez's selection was somewhat of a surprise, particularly with Leroy Sane left on the bench. The latter appeared to frustrate Pep Guardiola with his performance off the bench against Leicester, though, and Mahrez was given the nod down the right as Bernardo Silva dropped back into midfield.
As for Brighton, Anthony Knockaert and Beram Kayal came into the XI, while it was to be a special match for club captain Bruno, who recently announced that he would be retiring from football this summer.
Bernardo Silva had the game's first big moment as he danced into the Brighton box in the fourth minute, but the Portugal international was just crowded out by Yves Bissouma.
Brighton were having their moments with the ball, though, and Alireza Jahanbakhsh whistled one just wide of Ederson's post in the ninth minute, before Sergio Aguero missed a header from a Raheem Sterling cross down the other end.
Liverpool took the lead against Wolves in the 17th minute, and it was almost as if City knew as Mathew Ryan had to save from Sterling in the period that followed before Aguero struck wide of the post from distance.
Ryan was then called into action in the 23rd minute to palm clear a low drive from Mahrez, but it was the home side that incredibly took the lead in the 27th minute when Murray headed a Pascal Gross corner home at the near post.
City were behind for less than the blink of an eye, though, with Aguero levelling the scores in the 28th minute as he cooly slotted through the legs of Ryan after collecting a super flick from David Silva.
Ryan then had to keep out a header from Bernardo Silva moments later as the Portuguese continued to cause problems with his movement and work-rate in the final third of the field.
Mahrez saw another dangerous cross saved by Ryan during a strong spell of pressure, but City took the lead in the 38th minute when Aymeric Laporte headed a Mahrez corner into the back of the net.
A switch of position for Sterling, who moved back out wide, was bad news for Brighton as the England international continued to find space in the areas behind Seagulls captain Bruno.
Brighton actually almost equalised in the final stages of the first period when Lewis Dunk sent a powerful free kick towards the City goal, but Ederson was on hand to make a smart save.
Guardiola's side started the second period on the front foot, with Mahrez seeing a goal-bound strike blocked by Dunk during a spell where the home side were struggling to get out of their own half.
Bissouma was perhaps the pick of the Brighton players, but City were absolutely dominating the match, if not the scoreline, heading into the final 30 minutes of their Premier League campaign.
Ryan had to save from Sterling in the 61st minute, but City's third arrived three minutes later when Mahrez worked some space outside the penalty box before finding the top corner with an explosive strike. It was a goal that all but secured the title, with Brighton needing a miracle to hit back.
Gundogan struck wide of the goal in the 67th minute as the visitors looked for a fourth - the Germany international was not to be denied, though, and curled a wonderful free kick into the top corner for 4-1 in the 72nd minute.
As it turned out, there was to be no more drama as Guardiola's side kept the ball in the latter stages to ease their way towards their 32nd Premier League win of the campaign, which saw them win an extraordinary title.
Brighton finish the campaign in 17th position, while City will look to complete a domestic treble when they face Watford in the FA Cup final next weekend.
BRIGHTON (4-4-1-1): Ryan; Bernardo, Dunk, Duffy, Bruno (Montoya 84'); Jahanbakhsh (Locadia 67'), Bissouma, Kayal, Knockaert; Gross; Murray (Andone 67')
MANCHESTER CITY (4-3-3): Ederson; Walker (Danilo 88'), Kompany (Otamendi 86'), Laporte, Zinchenko; D Silva (De Bruyne 78'), Gundogan, B Silva; Mahrez, Aguero, Sterling