"It's a simple injury," said a raspy sounding Hamm in an interview Thursday. "Something that develops on your vocal cord from overuse because I talk a lot."
"Other than that, believe it or not, I'm healthy as a horse. Hoarse, get it?" he joked.
Hamm's publicist Erica Gray said he will undergo a routine outpatient procedure.
The condition hasn't slowed down the 42-year-old "Mad Men" star who was nominated for best actor at Sunday's Emmy Awards. Hamm lost to Jeff Daniels of the HBO drama "Newsroom."
"I'm OK with the results. I'm superhappy that Jeff won. I think his work is phenomenal," Hamm said. "I'm unabashed in my fandom for television so I had a great Emmys. I like going there and seeing a bunch of people and seeing my friends and it was fun. I got to present with Alec Baldwin. How fun is that?"
Ever the good sport, Hamm and actress Amy Poehler decided to throw a party for Emmy losers. To gain entry, winners were required to leave their trophies at the door and make a $1,000 donation to charity.
Much to Hamm's surprise, it was his new facial hair that made headlines the following day.
"I was out of the country and out of town for like four and a half months working and I was tired and so I came home and I was like, 'I'm not going to do anything. I'm not going to even shave,'" he said of his new full bearded look. "I guess that constitutes news."
Part of his time abroad included filming the second season of "A Young Doctors Notebook" in the U.K.
The miniseries, which also stars Daniel Radcliffe, is based on a collection of short stories by Russian playwright Mikhail Bulgakov.
"The show itself is very dark, but darkly comic and gory and fun," Hamm said. "It's not going to get the audience that watches 'Honey Boo-Boo,' which is fine."
The first season of "A Young Doctors Notebook" premieres Oct. 2 on Ovation.