0555 GMT June 23, 2018
Coleman's mark beat the previous record of 6.39 set twice by fellow American Maurice Greene, in 1998 and 2001, BBC reported.
The performance is subject to ratification by athletics' world governing body the IAAF.
"Great start to my career," tweeted Coleman, who aged 21 is in his first full year as a professional athlete.
It beats his previous best of 6.45, which he recorded when he won the US indoor championship last year.
"I'm in disbelief," said Coleman's coach Tim Hall. "This was his season opener. It was totally unexpected.
"We talked a little bit more before the final and like I always tell him, I said: 'Relax, no pressing and allow the run to happen’. That was the result."
Coleman ran 9.82 seconds, the fastest 100m of 2017, at the US outdoor collegiate title meeting.
Expected to be America's next great sprinter, he finished behind Justin Gatlin and ahead of world record holder Usain Bolt in the 100m at last year's world championships in London.
The 2018 World Indoor Championships take place in Birmingham from 1-4 March.