A late goal from substitute Michy Batshuayi was enough to end West Brom's resistance at the Hawthorns Friday, ensuring Antonio Conte's men cannot be caught with two fixtures left to play.
CNN Sport analyzes the London club's spectacular rise from tenth to the title.
While Mourinho was the architect of his own downfall -- squabbling with club doctor Eva Carneiro
before his undignified departure in December 2015 -- Conte has been the architect of Chelsea's revival.
His passion is infectious, and emanates from every pump of the fist.
Chelsea can conceivably finish this season with 93 points -- the most by any Premier League team aside from Mourinho's record-breaking side in 2004/05.
But how have they done it?
Conte used the word "work" 21 times in his first Chelsea press conference in July 2016.
The Italian made it clear that the players he had inherited would need to "fight," insisting, "When you finish 10th in the league ... the problem is not only one person."
He was right. That person, Mourinho, left because of alleged "palpable discord"
in the changing room, but the issues at Stamford Bridge ran deep.
Interim boss Guus Hiddink may have steadied the ship following his appointment in December 2015, but Chelsea still finished just 13 points above the relegation zone and as close to 18th as sixth.
Of the three clubs that made headline managerial appointments ahead of this campaign, the greatest expectations came from Manchester.
City and United spent a net total of $245 million on new players between them in the summer of 2016, rekindling the rivalry between Pep Guardiola and the Special One
Conte, meanwhile, quietly went about his business.
He had been here before, taking charge at Juventus when the Italian club was similarly resurfacing from the abyss -- coming to terms with the "Calciopoli" corruption scandal and Juventus' resultant demotion to Serie B.
Within a year, the former midfield general had led Juve -- dubbed the "Old Lady" -- to the Serie A title, the first Italian side to do so unbeaten since 1979.
Conte's influence was sufficient to prompt Juventus defender Leonardo Bonucci to compare his boss to a "hammer."
Fellow Italian Andrea Pirlo, meanwhile, wrote in his 2014 autobiography: "When Conte speaks, his words assault you."
The new manager has certainly shaken Chelsea's fallen stars into action.
Between August 2015 and 23rd April 2016, star player Eden Hazard didn't score a single Chelsea goal.
Mourinho had claimed his forward was the "best player in England" but, just as he had thrilled on his way to winning the 2014/15 PFA Player of the Year, Hazard quickly became symptomatic of the club's wider malaise.
Under Conte, the twisting, turning Belgian has thrown off last season's shackles to score 15 goals in 35 appearances.
Now he epitomizes Chelsea's dynamism.
This season, he has completed over 50% more take-ons per game (dribbles past an opposition player) and taken twice as many shots.
The 26-year-old could have passed when he picked up the ball in his own half during February's fixture against Arsenal.
Instead, he shrugged off the attentions of Francis Coquelin and waltzed past the Arsenal back line before slotting past his former teammate Petr Čech.
Diego Costa has also been brimming with confidence, becoming just the third Chelsea player to score more than 20 goals in a Premier League season on more than one occasion -- following in the footsteps of Jimmy Floyd Hasselbaink and club legend Didier Drogba.
There may be murmurings of a move to China, but the Spaniard has stepped up when it matters, scoring the opening goal on more occasions (7) than any other player in the Premier League this season.
It feels as if Chelsea's 3-0 collapse at the Emirates Stadium in September -- Conte's lowest moment and heaviest defeat since his days in charge of Siena -- occurred a lifetime ago.
"We are a great team only on paper, and not on the pitch," he said then, his bark reduced to a hoarse whisper. Chelsea hadn't won in three league games, languished in eighth place, and looked set for another season of mediocrity.
But Mourinho's successor didn't sulk or bicker. Instead, Conte took to the training pitch, steadily implemented his favored three-man defense perfected during three years in charge at Juventus, and went on to lead Chelsea to wins in the next 13 league matches.
Gary Cahill, David Luiz and César Azpilicueta were reinvigorated in the back three, keeping seven consecutive clean sheets and conceding just two league goals between late September and the new year.
N'Golo Kante has put to bed any suggestions he might be a one-season wonder, making more tackles and interceptions
than any other Premier League player since his arrival from Ligue 2, and picking up the PFA Player of the Year award.
Meanwhile Cesc Fabregas has been used sparingly, but still notched 11 assists in just 12 Premier League starts -- becoming the first player to reach double figures in six separate campaigns.
While his rivals have sought to spend to solve problems, Chelsea's change was not affected by a new starting 11.
Where Mourinho and Guardiola have arrived and attempted to mold teams in their own image, Conte has constructed the best system from the players at his disposal.
It stands to reason he may not have been afforded time to administer his tactical changes had Chelsea been burdened by European football.
But next season's challenges will be forgotten tonight as the champagne flows and the trophy is held aloft.
He is the fourth Italian manager to win the Premier League, the fourth manager to lift the top-flight trophy in his first season in England, and this is his fourth consecutive championship title as a club coach, having won Serie A with Juventus between 2011 and 2014.
He has, in his own words, transformed an "ugly duckling" into a "swan."