He does a dead-on impression of King, and his performances have impressed people who knew King when he was alive, including family members and notable civil rights leaders such as Andrew Young and the Rev. Jesse Jackson.
But Ferguson says he has never had an experience doing the speech like he had last week in Washington, D.C. On Thursday, he was visiting the Capitol Rotunda with a tour group, which wound up stopping next to a bust of King.
Ferguson hadn't been scheduled to speak but suddenly began reciting the speech, which King gave on the National Mall in 1963.
Ferguson initially thought he would only say a portion of it. But his voice rose and he kept on going - right until the end, as about 50 people formed a semicircle and watched in amazement.
A security guard told Ferguson later that such a display would normally not be allowed, but it was so moving Ferguson was allowed to continue.
"It really was just coming out of me," he says. "It just seemed like the spirit of Dr. King took over."
Video of Ferguson captures the moment and his chillingly accurate rendering of King's cadence and phrasing, which sound clear as a bell in the quiet Rotunda.
Says Ferguson: "It was like 'wow.' I really can't explain it."
Ferguson is an entertainer and a former radio news man who is officially licensed by King's estate to market himself as an impersonator. He knows all of King's major speeches and many lesser-known ones and has performed "I Have a Dream" at the annual MLK prayer breakfast in January and at other events.
Last May, he moved from Fayetteville to Atlanta where he is, as he says, "a 5-minute walk from the King Center in downtown Atlanta."
He had been in Washington since last Tuesday to take part in events leading up to the scheduled dedication of the new Martin Luther King Jr. National Memorial on the mall.
Officials postponed the event because of the hurricane, but Ferguson and about four others were taken on a tour of Washington sponsored by Faith and Action, a Christian nonprofit group that focuses on policy. Ferguson says the group had already passed the bust of King once before he gave the speech - he almost missed it, then went back to take pictures. The group walked into another room, then went back into the Rotunda, which he saw as a sign.
"We stopped right by this bust. I went like 'Wait, hold up, this is crazy.' We never went back to a place we came out of, except that one."
While in D.C., Ferguson also performed King's last speech at a private function attended by Naomi King, a daughter-in-law, and a King granddaughter, Alveda.
"Everybody in the room just teared up and had to pass around the Kleenex," he says.