Wise scooped the Nationwide Division One accolade after winning five out of six games in February, but his side were second-best all evening against a rejuvenated Blades outfit.
Neil Warnock's men - who had won just one league match in seven attempts prior to the game - were rewarded for a sustained spell of dominance when Ashley Ward swept the ball home just before the hour mark.
Andy Gray's predatory skills earned the Blades a second shortly afterwards but Millwall responded positively and Paul Ifill's wonderful volley handed the Londoners a lifeline after 69 minutes.
The Lions piled forward in search of an equaliser as United's rearguard was stretched to the limit.
But Millwall awoke from their slumber far too late and United hung on for three points which elevates them above the visitors in the table - and back into the First Division play-offs.
Following a scrappy start, United asserted some degree of authority on proceedings and carved out the best chance of the half when Phil Jagielka flicked a telling header across the face of goal for Ward, who forced goalkeeper Andy Marshall into a fine save shortly before the half-hour mark.
But the Blades have been worryingly porous in recent weeks and were nearly punished for their defensive frailties shortly afterwards.
A hopeful ball into their penalty area was not dealt with and from the resultant melee Tim Cahill somehow contrived to scuff his shot into the grateful arms of Paddy Kenny.
The second half followed a similar trend to that of the opening period - with United controlling the early stages. And shortly after Michael Tonge tested Marshall's reflexes with a teasing 25-yard free-kick, the Blades broke the deadlock after 58 minutes.
Sublime inter-linking play between Tonge and Jagielka unlocked the Millwall defence, and Ward supplied the finishing touch by bundling the ball home from close range.
Four minutes later United extended their advantage - albeit in controversial circumstances.
Darren Ward committed a rash challenge on namesake Ashley which sparked an unsightly 22-man fracas on the edge of the Millwall box.
The two Wards were shown the yellow card, as was Kenny, who needlessly became involved in the incident. Tonge's resultant free-kick was spilled by Marshall into the path of Gray who poked the ball into the back of the net from six yards.
Wise had seen enough and replaced Peter Sweeney and Marvin Elliott with Neil Harris and Mark McCammon 60 seconds later.
The double substitution had the desired effect and Millwall dragged themselves back into the contest when Danny Dichio's assist found Ifill, who unleashed a stunning volley that arrowed into the bottom left-hand corner of the net from 25 yards.