Gibbs, 64, admitted in response to reporters' questions that he went through the surgery in mid-April at a Washington hospital when a physical found the arterial blockage.
"I suffered no ill effects prior to the procedure, and have had none since," Gibbs said.
Gibbs said he told only close family members and associates, including Redskins owner Daniel Snyder, about the matter that he considers private.
Even so, NFL officials and observers have been discussing the state of the diabetic's health since he signed a five-year, $28.5 million contract in 2004, the Washington Post reported.
Gibbs, whose 6-10 record last season was the worst in his coaching career, said he expects to complete his contract and his doctors consider him in good health.