The Ghanaian midfielder netted a vital winner for the champions, who have ended their winless run and will now look to resume their title tussle with Juventus in the coming weeks.
An early strike from Sulley Muntari was enough for the Rossoneri to return to the summit, and although an uncomfortable night was endured by the Milanese outfit, they ground out the victory to edge two points clear of Juventus, having played a game more.
The champions gave a first league start of the season to Mattia De Sciglio at left back, while Gennaro Gattuso was welcomed back into the starting XI for the first time since September as the visitors' injury problems were made plain. But even he failed to provide inspiration to what was a lacklustre Milan display.
An uncertain beginning to the match saw Massimiliano Allegri's men frequently squander possession, with Michael Bradley and Co. doing their utmost to unsettle thei lethargic visitors, who struggled to stamp their authority.
But they were able to claim an early advantage. A counterattack led by Robinho found teammate Muntari, who, helped by a bobble, fired a low shot from distance past Stefano Sorrentino for the lead.
However, the goal did not act as a tonic for Allegri's side, and Chievo will have been deeply disappointed not to have found the equalizer before the interval.
Frenchman Cyril Thereau was presented with a headed opportunity following Luca Rigoni's good work, but Christian Abbiati played a key role in ensuring his net was not exploited throughout the encounter.
Robinho again flattered to deceive in a Milan jersey, but he came agonisingly close to doubling the lead for his side after some magnificent individual play. The Brazilian shifted past Francesco Acerbi, but his left-footed strike came a whisker away from beating Sorrentino.
The status quo was carried over into the second half, as Chievo again dominated much of the play. It restarted with two more chances, but Bradley's strike was straight at Abbiati, while Sergio Pellissier failed to make the rebound count, blazing hopelessly over the bar.
The Flying Donkeys' endeavor showed no signs of abating, and the introduction of Luciano promised more inventive football from the hosts. However, Milan remained rigid in its approach and continued to keep the result in its favor.
The remainder of the contest saw opportunities at a premium. Domenico Di Carlo's men did not throw in the towel and did their best to salvage what they could, but Pellissier, who tried his best to act as a target man, had little to work with.
Alessandro Nesta's handball in the box was the only other noteworthy incident, but the defender threw up his arm for an offside call, which referee Paolo Valeri correctly agreed with.
The hosts' last action saw them find the net in injury time, but the effort was adjudged to be offside, and Milan now moves two points clear of archrival Juventus at the top of Serie A, with the Turin giants facing Lazio on Wednesday.