Mourinho's side were gifted an early chance to get their season off to the perfect start when referee Jonathan Moss pointed to the spot following Hull goalkeeper Alan McGregor's collision with Fernando Torres. However, the Scottish international was able to redeem himself, pulling off a fine save to deny Frank Lampard from 12 yards.
The hosts controlled the opening stages of the game, with their pressure paying off on the 12 minute mark when Brazil midfielder Oscar poked the ball under McGregor after being played in by Kevin de Bruyne.
Lampard atoned for his spot-kick miss to double Chelsea's lead with a long-range free-kick midway through the first-half as the Blues threatened to run riot. He was then unlucky not to make it three just before the break when McGregor denied him with a smart save before Branislav Ivanovic was also thwarted by the Scotsman who palmed away his powerful header.
As the hour mark approached, Hull boss Steve Bruce introduced new signings Tom Huddlestone and Jake Livermore who both arrived from Tottenham earlier this week. The Tigers put in a spirited display after the interval and they came closest to pulling one back when Petr Cech caught Curtis Davies' goal-bound header.
Despite Hull's resilience as the game drew on, chances for either side were few and far between as Mourinho enjoyed a winning start to his second spell in the hot seat at Stamford Bridge.
Belgium forward de Bruyne has been a Chelsea player since January 2012 and finally made his competitive debut behind Torres, who was preferred up front to Romelu Lukaku.
McGregor saved from Eden Hazard before felling Torres with a clumsy challenge which conceded a penalty.
Lampard saw his spot-kick saved, but it appeared only a matter of time before the visiting defence was breached.
Hazard received the ball on the left, cut inside and found De Bruyne, who fed the on-running Oscar and the Brazilian prodded underneath the advancing McGregor.
The Scot again denied Lampard, this time from the edge of the area, as Chelsea pressed forward relentlessly in search of a second.
It came after Torres was awarded a dubious free-kick 30 yards out, against James Chester.
Lampard's rapier-like strike dipped into the top corner past McGregor and Chelsea's record goalscorer wheeled away, racing towards the dugout and his manager.
Mourinho turned his back, though, focusing on what would happen next and leaving Lampard to celebrate with his team-mates.
Hull will have less difficult days than this in the top flight, but they did little to help themselves, giving possession away cheaply.
Lampard had another shot saved as half-time approached and, from a corner, Ivanovic had a header blocked on the line by McGregor.
There was no reaction from referee Moss, whose watch did not buzz - it would alert him if the ball had crossed the line - and Hull were relieved to be only two down.
Chelsea were content to bide their time in the opening exchanges of the second period and home goalkeeper Petr Cech was required to make a save for the first time when Robert Koren shot straight at him.
The Tigers were fortunate not to concede a second penalty when Ivanovic was pushed over by Robbie Brady before Hull appealed in vain for handball when Yannick Sagbo's shot was driven at Lampard's chest.
The arrivals of Huddlestone and Livermore gave Hull more of a midfield presence and Cech was forced into another save when Ahmed El Mohamady's right-wing cross found Curtis Davies, whose header extended the goalkeeper.
Andre Schurrle and Lukaku replaced De Bruyne and Torres as Mourinho sought a fresh impetus which never came.
Schurrle chipped over when played through by Ramires but Mourinho had to be content with a 2-0 victory.