The Colombian forward was the catalyst behind LAFC's comeback win, which kept them within touching distance of the Western Conference's Audi MLS Cup Playoff places with four regular-season games remaining.
LAFC fell behind again after conceding to FCD's Franco Jara in the 45th minute, but Arango ensured the victorious result with additional tallies between the 75th and 79th minutes.
The first of those was set up by Danny Musovski's pinpoint feed, which Arango cashed home with a clinical first-time finish for his second equalizer of the match.
Wednesday's hat trick continued Arango's torrid run of form since his early August arrival from Millonarios, with the trio of goals giving him 11 in just 13 MLS games as he continues to build an MLS Newcomer of the Year case. The 26-year-old has kept LAFC afloat in the Western Conference playoff race, with Wednesday's victory leaving them three points shy of the West's final playoff spot.
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 the vote. NASR consists of members of print, television, radio and online media.