The under-fire Foxes made a dream start to the match when they opened the scoring through Kelechi Iheanacho inside the first minute, but they were behind just 15 minutes later as a Luke Thomas own goal and Moises Caicedo strike quickly turned the game on its head.
Patson Daka then levelled things up shortly after the half-hour mark, and Brendan Rodgers's side had a reprieve shortly after half time when Alexis Mac Allister's thunderous first-time half-volley was ruled out by VAR due to an offside in the buildup.
However, on a weekend of costly and controversial VAR calls, this one did not have a decisive impact on the result as goals from Leandro Trossard and Mac Allister (2) - the latter from the penalty spot and then a direct free kick - secured a return to winning ways for the Seagulls, who score five goals in a top-flight game for the first time ever and move into the top four courtesy of this result.
Leicester's miserable start to the season, coupled with a summer transfer window which frustrated Rodgers, meant that they came into today's match under huge pressure, but they made a perfect start when Iheanacho tucked Daka's low cross into an empty net from inside the box.
That lead lasted just nine minutes, though, as a lofted ball to the back post was met by Solly March, whose attempted header back across goal bounced off Thomas and crept over the line.
The quickfire turnaround was complete five minutes after that when Enock Mwepu drove forward with the ball before laying it off for Caicedo, who planted his finish firmly into the far corner.
While some key players left Leicester, it was one of those who stayed who created the equaliser as Youri Tielemans floated a long pass forward for Daka to run on to, and the striker finished with aplomb to send the two sides into the break all square.
VAR once again came under scrutiny soon after the restart when Mac Allister's piledriver was ruled out for an offside against Danny Welbeck during the free kick which immediately preceded the goal.
However, Brighton were not to be deterred and Trossard restored their lead shortly after the hour mark when he latched on to Pascal Gross's pass before sweeping his finishing into the far corner.
Mac Allister would also not be denied, and having seen his earlier stunner controversially chalked off, he capped off the scoring with a set-piece brace - including another brilliant long-range strike.
The first came from the penalty spot after Trossard had embarrassed Wilfred Ndidi with an audacious piece of skill, drawing the Leicester man into an ill-judged foul which Mac Allister duly punished.
A brilliant free kick capped off his fine solo showing in the 97th minute as Brighton reached the five-goal mark for the first time in their top-flight history, moving into the Champions League places in the process.
However, while Brighton were left to celebrate their fantastic five, for Leicester it is now five defeats in a row for the first time since the final five games of Claudio Ranieri's reign, and Rodgers's future will come under the spotlight even more following the second-worst start to a season in the club's history.