The 25-year-old, on loan from Liga MX's Chivas Guadalajara, enjoyed a dream start with a third-minute strike that he smashed past Chicago goalkeeper Gaga Slonina, off the underside of the crossbar and into the net.
After the Fire equalized through Chinoso Offor, Cisneros restored the lead after Luiz Araujo saw his initial cross deflected by Slonina. He then completed the 33-minute hat trick by converting a breakaway finish that pushed Atlanta's lead to 3-1.
That all allowed the Five Stripes to hit cruise control, with Brooks Lennon adding a late insurance tally to round out the scoring.
It was a breakout showing for Cisneros, who's taken a key role for the Five Stripes with star striker Josef Martinez sidelined due to a procedure to clean out debris in his surgically repaired right knee. Cisneros has now made five MLS appearances this season (four starts), with Saturday's outburst giving him four goals in 375 minutes.
Atlanta, meanwhile, got a much-needed three-point result that snapped a four-match winless streak and put them back above the Audi MLS Cup Playoffs line in the Eastern Conference table.
The Five Stripes return to league play Sunday when hosting the New England Revolution (1:30 pm ET | ESPN, ESPN Deportes), looking to extend their 12-game unbeaten run at Mercedes-Benz Stadium.
The MLS Player of the Week is selected each week of the regular season through both media and fan voting in a process conducted by MLS Communications. A panel of journalists from the North American Soccer Reporters (NASR) comprises 75 percent of the vote, while a Twitter fan vote represents the remaining 25 percent of voting. NASR consists of members of print, television, radio and online media.