The 34-year-old striker looks set to enter the new year with renewed vigour after his second-half header saw Neil Harris’ side successfully build on their fine Boxing Day draw with Sky Bet Championship pace-setters Wolves.
The hosts’ victory also handed Ian Holloway an unhappy return to his old club.
The first sight of goal fell to Millwall winger Aiden O’Brien, who stabbed over the bar from the edge of the six-yard box, and soon afterwards visiting defender Grant Hall survived handball shouts from the stands after he blocked Lee Gregory’s attempted cutback in the area.
Morison failed to get the required power on an O’Brien cross as Millwall continued to exert early pressure, while at the other end QPR wing-back Pawel Wszolek volleyed well wide after the Lions part-cleared a Jake Bidwell set-piece from the left flank.
That summed up the first quarter of a contest lacking any real decisive quality, with veteran frontman Morison fluffing his lines when he met a delicately floated right-wing cross in the 27th minute.
The impressive George Saville forced Alex Smithies into a reaction save with his follow-up, and in a flash Millwall’s Gregory found space to turn in the area and let fly but his snap-shot was knocked away by a despairing Hall.
Having fully awoken from their slumber, the Lions bared their teeth again as Jed Wallace slipped away from his marker and fired into the side-netting.
Then, with 35 minutes played, QPR defender Alex Baptiste picked out Bidwell with an inch-perfect delivery from the right wing but Jordan Archer was equal to his header.
Archer also had to be alert to gather a glancing header from Luke Freeman early in the second period, the wily midfielder redirecting Jordan Cousins’ cross.
Millwall skipper Morison atoned for his earlier miss when he made the 55th-minute breakthrough, the former Norwich man straining his neck to power home Wallace’s inviting right-wing delivery.
A misjudged defensive header from Nedum Onuoha almost gifted the Lions a second in a flash, with Smithies forced to charge off his line to stand up to the onrushing Gregory.
At the other end, Archer just about kept hold of a bouncing Massimo Luongo effort.
With time running out, QPR substitute Matt Smith met a Freeman corner but saw his header drop just wide.