Ross' reign did not get off to the best start as the capital club fell behind to a Liam Polworth strike in the ninth minute.
However, Christian Doidge's fourth goal in two games restored parity on 21 minutes and Florian Kamberi edged the hosts ahead four minutes later, before a fine solo effort by Daryl Horgan added gloss to the scoreline four minutes from time.
The result marked a second win on the spin for the Hibees, who also hit the post through Stevie Mallan, and sent them into the top six.
There was a wholly inauspicious start to the afternoon for the home team, when the Steelmen grabbed an early lead. Jermaine Hylton danced into the box before finding Jake Carroll, whose low shot struck the post and fell kindly for Polwarth to tap home the rebound.
Hibs responded admirably and levelled through Doidge. Kamberi found Joe Newell with a fine through-ball and, although the winger's shot was partially blocked by the out-rushing Mark Gillespie, the towering marksman managed to bundle the ball over the line.
The hosts completed the swift turnaround midway through the first half as Scott Allan made his mark.
Allan produced a sensational through-ball to Jason Naismith and the full-back's low cross deflected into the path of Kamberi, who showed admirable composure and fleet of foot to fire into the roof of the net in a crowded box.
Gillespie was forced into action as Hibs sought to make the game safe after the break, making a sharp save to deny Doidge following some superb interplay between Kamberi and Allan.
For all their inventive attacking play, the Hibees were fortunate not to concede a penalty on the hour mark when Ryan Porteous appeared to haul Polwarth down in the box. The visitors howled for a spot-kick, but referee John Beaton remained unmoved.
And Hibs added a third after 86 minutes with a classy counter-attack. Vykintas Slivka found Mallan, who slipped a fine pass to fellow substitute Horgan. The Irishman did the rest, scampering forward and clinically firing beyond Gillespie.
There was even time for Mallan – a star under Ross at St Mirren – to strike the base of the post, but the points were assured.