Crimson Consulting's director Jamie Beaton said Mr Key approached the company about the role, which makes him one of about six sporting consultants for the company in Australasia, plus about 60 contractors in the US and UK.
"Max is a phenomenal achiever in baseball ... He's going to help inspire Kiwis who want to get abroad for sport."
The pair knew each other from school, but Mr Beaton stresses fame has nothing to do with the selection of his latest employee.
"I don't really care if someone is Britney Spears. I care about ability and talent. We don't select any of our consultants based on anything but the requirements for the job.
"I'm not really interested in the PR stuff and I wouldn't want that to detract from Max's exceptional ability and talent in the field and to work with students," he said.
Mr Beaton, 20, and his partner set up Crimson Consulting in 2013.
The former St Kentigern and King's College student will finish his bachelor and masters degrees next year at Harvard after thee year of study, two years ahead of the typical schedule. "It's been quite intense," he says.
He said half of his secondary schooling was funded through scholarships and financial assistance.
A spokeswoman for Prime Minister John Key said: "Max sees [Crimson Consulting] as a great opportunity to broaden his own skill set and help ... other young New Zealanders trying to make their way into top sports colleges and universities."