The 39-year-old Dane took nine victories during his pro career, which was otherwise often spent working for his teams' leaders on the front of the peloton for hours on end.
Those victories, however, included a solo stage win at the 2012 Giro d'Italia and French one-day race Paris-Bourges in 2005. He also won the Danish national title on the road that same year, and went on to win the national time trial championships in both 2007 and 2008.
His last win was a spectacular solo effort at the GP de Fourmies back in 2012, when he held off a rapidly approaching peloton to beat Alexander Kristoff and Marcel Kittel by a single second.
It came as part of a hugely successful first year at what was then Lotto Belisol – now Lotto Soudal – with whom Bak spent seven seasons before making the move to Dimension Data for 2019. He also rode for Fakta, Bankgiroloterij, CSC and HTC.
"I made this decision public at the end of the Tour de France, so I have had enough time to reflect, even though there were still races to do," Bak said on the Dimension Data website ahead of Sunday's Paris-Tours.
I am very motivated to end my career on a high note," he said. "During the week, I went down memory lane, looking back on all the things I have achieved in my career. I have had so many messages from people, from the start of my career to now, just reminding me of my whole career...
"I have had 18 great years, but nothing lasts forever. I know it is the right decision. I think I have done my duty. I've left all my energy and power on the road. And now I want to do it one last time on Sunday. I hope I can ride a good race. It is going to be special."
And indeed it was, with Bak finding himself in the thick of the action, but unable to pull back former Lotto Soudal teammate, and the day's winner, Jelle Wallays.
"There were some crashes that split it up in the feed zone, and then I was caught up in the first chase group," Bak said in a video posted by Dimension Data on Twitter after the finish of the Dane's last pro race.
"Then we reached the front group, and I just survived all the pavé [gravel] with Julien [Vermote]," he continued. "Reinardt [Janse Van Rensburg] was unlucky – he punctured – but Julien and I were still up there.
"I was really going for the podium, but I hesitated at one point in the last five kilometres, and then I didn't go with Niki Terpstra [Total Direct Energie] and Oliver Naesen [AG2R La Mondiale]," said Bak, with the Dutchman and Belgian taking second and third.
"Anyway, it's a good way to stop, with a top 10 at Paris-Tours. I didn't dream about that this morning, so I'm really happy to stop like this," he said.
🇨🇵 #ParisToursJelle Wellays (LTS) wins @ParisTours.What a ride from @LarsBak16 who finishes 7th on the day to cap a fine career!"I didn't dream to finish like this!" #TakLars🎥: @AliceJRaw pic.twitter.com/An1FMEN5I1October 13, 2019