The Blues moved to re-appoint 'The Special One' last summer after making their way through Andre Villas-Boas, Roberto di Matteo and Rafael Benitez within the space of two years, and the return of the Portuguese boss was the sign of stability returning to Stamford Bridge.
Yet it was also the signal for optimism once again. Mourinho's spell with Real Madrid may have ended bitterly, but there was still no doubt that he was the man to take Chelsea forward, and many thought that Mourinho's arrival - coupled with Sir Alex Ferguson's retirement at Manchester United - would lead to the Premier League title heading back to West London.
Yet with just one game to play, the Blues are all but out of the title race, barring collapses from Liverpool and Manchester City. It's a disappointing end to the season, particularly after we all watched Mourinho's men show off their title credentials with a superb win at City in February.
The trophy-less season marks the second calendar year in a row where Mourinho has failed to win a trophy, but it's only the second since 2003. This season may have ended in a disappointing fashion, but how successful has his first season back at Stamford Bridge been?
Last week's Champions League exit to Atletico Madrid was hugely disappointing having fought so hard to see of Paris Saint-Germain in the previous round as well as to earn a draw in the first leg against Atleti a fortnight ago. The Premier League challenge has fallen by the wayside, and it seems few Blues fans will be cut up about losing out on the FA Cup and League Cup trophies.
There have been glimpses of what version two of Mourinho's Chelsea could look like, and with young talents such as Cesar Azpilicueta, Nemanja Matic, Willian, Oscar and Eden Hazard - as well as the returning Romelu Lukaku and Thibaut Courtois - the future certainly still looks bright in West London.
But whilst the Blues may be many people's favourites to be Premier League winners next season with a summer of spending expected, this season has ending in a disappointing manner, and Mourinho has to improve next season or risk the unthinkable - being sacked once again by owner Roman Abramovich.