For starters, he’s 48.
He’s also a millionaire businessman.
So what is he doing in Sochi, throwing 44-pound slabs of granite rock down a 46-foot sheet of ice?
In an everyman sport full of characters with interesting backstories, Jahr - the oldest curler competing in these Winter Games - probably has one of the most captivating of the lot.
He is a major shareholder in two casinos, including one in his home town of Hamburg in northern Germany. He controls part of a huge German publishing house, Gruner + Jahr, which was co-founded by his grandfather and brought in revenues of 2.22 billion euros (now $3 billion) in the financial year of 2012. And he spends most of his time working in property development and investment management.
“I work in this and that,” he says, with a smile.
For the past four years, and especially the last six months, his business interests have taken a back seat.
Curling has been his No. 1 priority.
Jahr was a successful player in the 1980s and ‘90s. He was a member of Rodger Gustaf Schmidt’s European championship-winning team in 1985 and also won a silver medal with the same rink in the 1987 world championship. He skipped his own team for the 1996 world championship.
He hung up his broom in 2000, deciding - in his mid-30s - to focus on business. But there was an itch he still needed to scratch - he hadn’t competed at an Olympic Games.
So, in 2010, he returned to the ice with a team from Curling Club Hamburg, a club his father founded.
“It was hard coming back, yes,” Jahr recalled. “It was not the technique, I still had that. It was the skill of thinking strategy. I lost it. It needed half a year to come back with my head in the game.