This was the first time that the 24-year-old Polish tennis star had reached the quarterfinals, while Federer was appearing in his 18th.
If the eight-time champion's exit was a surprise, the manner of it was even more so -- Hurkacz triumphed in three sets -- 6-3 7-6 (7-4) 6-0.
The 39-year-old Federer was seeking to become oldest man to reach Wimbledon semifinals in the Open era, but he looked a shadow of the player that has graced Centre Court over so many years.
The Swiss star made 31 unforced errors; Hurkacz made just 12.
Federer underwent two knee surgeries in 2020 and had been targeting a ninth Wimbledon title on his favorite grass court surface.
In June he had withdrawn from the French Open after his third-round win over Dominik Koepfer to protect his knee.
Federer's defeat on Wednesday was only his 14th in 119 matches at Wimbledon and his first straight sets loss at the grass court grand slam since 2002, the year before his first championship there.
"I noticed the mishits, awkward looking points from Roger and obviously the last set of course, 6-0," three-time Wimbledon champion Boris Becker told the BBC.
The goal is to play
Facing the media and asked if he was considering retirement, Federer replied that stopping playing wasn't on his mind.
"No, it's just about having perspective," Federer told reporters. "You need a goal when you're going through rehab with what I did.
"You can't think of the entire mountain to climb as once. You got to go in steps. Wimbledon was the initial first super step.
"For me, now that that's over, you just got to reassess everything. You have got to sit down, talk about it, what went well, what didn't go so well, where is the body, where is the knee, where is the mind?
"I've just got to talk to the team, take my time, not feel rushed by you guys [the media] or anybody else, for that matter. I've got to take my time, take the right decision, the one decision I want to take and where I feel most comfortable.
"That's where it leaves me. But, no, I hope not that that's going to happen. The goal is to play, of course."
Hurkacz will be contesting his first grand slam semifinal -- he is only the second Polish man to reach the Wimbledon last four after Jerzy Janowicz did it in 2013.
The Pole will face Italy's Matteo Berrettini on Friday, while Novak Djokovic will meet Denis Shapovalov in the other semifinal.
Chasing his 20th grand slam title, Djokovic defeated Hungary's Marton Fucsovics 6-3 6-4 6-4 on Wednesday, while Canadian Shapovalov overcame Russia's Karen Khachanov 6-4 3-6 5-7 6-1 6-4.
Meanwhile Berrettini got the better of Canadian Felix Auger-Aliassime, with the Italian winning in four sets -- 6-3 5-7 7-5 6-3.