The 62-year-old told the league in July about the 2012 email and details were yesterday revealed after an internal investigation led by commissioner Adam Silver.
"I wrote an e-mail two years ago that was inappropriate and offensive," Levenson said in a Hawks statement yesterday. "I trivialised our fans by making cliched assumptions about their interests (i.e., hip hop vs. country, white vs. black cheerleaders, etc.) and by stereotyping their perceptions of one another (i.e., that white fans might be afraid of our black fans).
"By focusing on race, I also sent the unintentional and hurtful message that our white fans are more valuable than our black fans.
"If you're angry about what I wrote, you should be. I'm angry at myself, too. It was inflammatory nonsense. We all may have subtle biases and preconceptions when it comes to race, but my role as a leader is to challenge them, not to validate or accommodate those who might hold them."
Levenson's confession comes after he was one of the strongest critics among other NBA owners of Donald Sterling, the Los Angeles Clippers owner who was recorded making racist comments and banned for life from the league.
Silver said in a statement that Levenson had apologised for his actions.
"He shared with me how truly remorseful he is for using those hurtful words and how apologetic he is to the entire NBA family — fans, players, team employees, business partners and fellow team owners — for having diverted attention away from our game," said Silver.
Levenson had been the Hawks' governor and controlling owner since 2004. Chief executive officer Steve Koonin will now take over team operations until a buyer is found.
You can read the full email text by clicking here.