Holloway beat Edgar by unanimous decision, receiving scores of 50-45, 50-45 and 48-47.
This was Holloway's first appearance since losing to Dustin Poirier for the interim lightweight title at UFC 236 in April. It was also his first fight at 155 pounds since joining UFC in 2012.
Despite that defeat, Holloway said coming into his bout with Edgar that he learned a lot from challenging Poirier.
"Losing is losing. It's only a loss if you haven't learned from something," Holloway told KHON 2's Ren Clayton. "I learned from it. I don't take no L's. The only L's I'm taking is Learning curves. And we got a learning curve in April. Everything is like shoots and ladders. Sometimes you got to slide down to climb up a bigger ladder and that's what we did."
Moving back to his traditional 145 pounds got Holloway right back on track. The 27-year-old hasn't lost at this weight since August 2013, a streak of 14 fights. He's also one of only two lightweights in UFC history to successfully defend the title multiple times. Jose Aldo holds the all-time record with seven, followed by Holloway's current total of three.
Edgar has his own streak going, though it's one he would like to forget. The Answer has now lost each of his last five title fights dating back to 2012.
One thing Edgar has been able to do late in his career is reinvent himself. He rebounded from three straight losses from February 2012 to February 2013 by moving up in weight to avoid taking on challengers who were quicker than him.
Being 37 years old with 31 career fights certainly explains why Edgar continues to struggle against top-tier competition. He's still good enough to keep himself in title contention, but Saturday was another disappointing finish for the future Hall of Famer.