But over their 16-year friendship, the Spotify cofounder has drawn at least one red line in his relationship with the billionaire: playing sports.

Zuckerberg has found a second lease on life in recent years through his newfound affinity for mixed martial arts (MMA) and surfing, which has helped him update his style in the process.

However, Ek has not been keen to make these interests a shared hobby, owing to the pair’s mutual love of competition and hatred for losing. 

“The rule I have with Mark is I don’t try to go into a competition with him because I know it’ll end badly for both of us,” Ek told the Acquired podcast.

“As you know Mark likes sports, so one of the things I don’t do with Mark is play sports for exactly this reason.

“The last time he sort of tore his ACL with someone rather than giving up, so I feel like it would end pretty badly,” Ek added, referring to an injury Zuckerberg sustained in MMA training last year.

“I like playing when I know I’ll win, so I think it’s a pretty good thing not to do that.”

Ek and Zuckerberg’s friendship

Ek said he first met Zuckerberg at a barbecue in 2008 after being introduced by early Facebook and Spotify player Sean Parker, where the pair riffed off ideas to make Spotify more social through Facebook’s feed.

At the time, Spotify was still operating an invite-only model to build hype around the streaming service’s exclusivity, aping Zuckerberg’s early Facebook model that required specific college email addresses to sign up.

The pair recently coauthored an open letter calling for more consistent AI regulation in the EU, arguing that failure to do so could cause Europe to fall behind other regions.

The Spotify cofounder has also learned valuable leadership lessons from the Meta founder over their friendship, saying Zuckerberg was the best learner he had ever seen.

“You can have a conversation with him about a topic, and he may not know very much about it, and then the next time he would know more than I would say most experts about the subject.”

Ek has also learned from Zuckerberg’s meeting style, saying the Facebook cofounder hosts an average of 15 to 20 people in a meeting. 

Swedish CEO Ek takes a more Scandinavian approach to running his company. He has leaned on the Scandinavian leadership model and says he is probably the least powerful person at Spotify because of how he delegates responsibility.

Speaking last year, Ek said the world had met three Mark Zuckerbergs during their friendship.

First was the “Social Network–era Mark,” referring to the unfortunate reputation he gained after the release of the Oscar-winning movie starring Jesse Eisenberg. 

Then came “Cambridge Analytica Mark” or “Evil Mark” after Facebook shared the data of millions of Americans with the political consultancy Cambridge Analytica, causing huge ramifications for data privacy.

Finally, Ek says, is “Mark 3.0,” someone who has recaptured his ruthless edge with the help of his burgeoning second life as a fighter and a surfer.

“He’s learned a lot over these past few years and he has a new fire in the belly. He’s realized he needs to act responsibly because he’s got this enormous platform,” Ek told Forbes last year.

“But there’s still some of the old Mark, where he is betting on things even though everyone tells him, ‘This is never gonna work.’”