On January 25, the Portuguese signed a one-year extension to the deal he penned upon his arrival at Old Trafford in 2016, and he plans to ensure United are a force again on all fronts.
He also hinted at further major additions to the squad when asked where he sees the team in two years' time, per BT Sport (via ESPN.co.uk's Rob Dawson): "Better than now. Fighting for what we are fighting for now but with different ammunition. I see us being real contenders for everything, that's the level we want to achieve."
In Mourinho's debut season in charge at United, he led the club to UEFA Europa League and EFL Cup glory, but the Red Devils finished sixth in the Premier League.
They are second in the 2017-18 league table, as they have been for much of the season, but they are a whopping 15 points back from leaders Manchester City after a 2-0 defeat to Tottenham Hotspur on Wednesday.
United's League Cup defence ended at the quarter-final stage this season, but they have made it to the last 16 of the UEFA Champions League and the fifth round of the FA Cup.
In the Champions League, United need to get past Sevilla if they are to reach the quarter-finals for the first time since 2014, with the first leg of their tie with the Spanish side scheduled for February 21.
The Mail on Sunday's Oliver Holt believes United have a decent chance of being a force this season in Europe's premier club competition:
But it is clear there is still a gulf between United and Europe's elite, not least their neighbours City, who are managed by Mourinho's long-term rival, Pep Guardiola.
Since Sir Alex Ferguson left Old Trafford in 2013, United's standing in the European game has fallen somewhat as they have been unable to launch a genuine title challenge.
Under Mourinho, though, they have been edging back to their previous status.
They are some way off matching the quality of United's last Champions League-winning side in 2008, but it is clear Mourinho's ambition is to make the Red Devils a major European force once again.