The 26-year-old winger created goals for Ross Stewart and Brian Graham, then smashed one in himself, stirring wild scenes in Dingwall.
Graham’s second added extra fizz late on as the double trophy-winning Staggies booked a Premiership comeback only a year after their disastrous drop.
Queens remain only three points clear of the automatic relegation place at the foot of the table and will nervously eye rival results today.
County are back where they feel they belong, this time no longer the wide-eyed new boys, but ready for a second coming after six past years at Premiership level. It means the Staggies have succeeded where Rangers, Hibs and Dundee United have failed in exiting the Championship at the first time of asking.
Inside seven minutes, County passed up a great chance when Josh Mullin’s low-driven cross from the right ricocheted off the long legs of striker Brian Graham, only three or four yards out, and spun to the safety of the keeper’s arms.
County fans in the club’s Jail End unfurled a flag criticising the BBC’s enforced rescheduling of the match from the Saturday billing, but the mood was mostly celebratory.
But Queens then served a reminder that the league was not yet won, as Kyle Jacobs cracked an attempt against the legs of County keeper Scott Fox.
Fox was brilliant, again, after 18 minutes when the lively Andrew Stirling’s cross smacked off home defender Andy Boyle.
The County keeper reacted like lightning to palm the ball away from his bottom-left corner.
But a party was brewing when the home breakthrough came just before the half-hour mark. Josh Mullin’s swerving corner from the left veered into the Queens six-yard box and Ross Stewart stooped in front of defender Michael Doyle to hammer in a header.
Moments later, County’s Brian Graham controlled and rocketed a volley just over the bar from a couple of feet inside the penalty area.
Inside the final five minutes of the first half, Queens defender Michael Doyle unleashed a ferocious 30-yard attempt that had Fox beaten but struck the crossbar.
Winger Mullin, who gambled on eschewing Livingston’s top-flight campaign last summer, staying in the Championship with a move to Dingwall, has been one of the season’s revelations.
The winger’s second assist of the evening – and 21st of the campaign – brought the house down five minutes into the second half. A pinpoint delivery from the far right this time found striker Graham stooping to power a header home.
Mullin’s goals from the wide area have also been huge for County and, four minutes later, he claimed his 14th of the campaign in stunning fashion. The winger took a Declan McManus pass before rocketing a fabulous 22-yard strike past Deniz Mehmet from just inside the D.
Queens offered little in response and substitute McManus dragged another attempt just wide, while Graham knocked another brilliant Mullin delivery wide.
Liam Fontaine’s return after rupturing his achilles in November cranked up the volume, as did Iain Vigurs’ return after an identical period.
They noise erupted again as Graham smashed in another header from Tom Grivosti’s cross.
But the biggest cheer greeted the final whistle, sparking a long night of celebration.