Coates said in an interview
with "Democracy Now!" that he was "stunned" after Sanders cruised to victory in New Hampshire.
"Had you told me this a year ago, I certainly would not have expected an avowed socialist to be putting up these sorts of numbers and contending for the Democratic Party nomination," Coates said. "But I think it's awesome. I think it's great."
Coates, a correspondent for The Atlantic and author of the best-selling "Between the World and Me," rose to national prominence in 2014 with the publication of his article, "The Case for Reparations." Already an acclaimed writer, the essay earned him a place among the country's most influential African-American social and political commentators.
In his interview with Amy Goodman on Democracy Now!, Coates said he planned to back Sanders despite concerns -- well documented in a recent article
in The Atlantic and a subsequent exchange on social media
with the rapper and Sanders supporter "Killer Mike" -- about the Vermont senator's focus on economic issues.
"One can be very very critical of Senator Sanders on this specific issue, one can say Senator Sanders should have a more explicit anti-racist policy within his racial justice platform, not just more general stuff, and still cast a vote for Senator Sanders, and still feel that Sen. Sanders is the best option that we have in the race," Coates said.
He also expressed some worry about Hillary Clinton's record, referencing her time as first lady during former President Bill Clinton's presidency.
"I'm very, very concerned about where her positions were, when we had some of the most disgusting legislation in terms of criminal justice in this country's history," Coates said.
On Twitter after his conversation with Goodman, Coates sought to temper enthusiasm among Sanders supporters, writing
, "This ain't 'feeling the Bern.' It's just trying to be a decent citizen and as transparent as I can be."
The public expression of support, he said earlier
, should not be confused with an "endorsement."
"That's me, the citizen," Coates tweeted
. "Me, the writer doesn't speak for anyone else and doesn't intend to try to sway anyone else."