In his first public appearance since the that announcement, Lewis accepted a lifetime achievement award from the Nevada Broadcasters Association, saying that he made his reputation in show business by saving lives.
"I made my reputation in this business caring for what I did, caring for the people that I did it for," said Lewis, who donned a red foam clown nose at one point during his speech in front of politicians and other entertainers.
"Let me tell you that saving lives is a very, very special project in the life of any man who wants to do that, but I have had the joy of ... extending my life by what I feel in my heart," he said.
Lewis hinted during his brief speech that he could not explain why he is no longer the national chairman of the MDA after 45 years. He will also no longer host the group's annual Labor Day weekend telethon.
Lewis said he was humbled to hear several congressmen and Nevada Gov. Brian Sandoval describe watching Lewis host the MDA's annual Labor Day weekend telethon every year throughout their childhoods.
"It was as meaningful tonight as ever," the 85-year-old said of his charitable work. "And I don't think I can go into the why of that."
Lewis appeared briefly at the dinner, entering just before his tribute and leaving the room minutes after making his speech. He declined to speak to reporters as he left the event.
In May, Lewis said in a statement issued through the association that he would make his final appearance on the telethon this year and sing "You'll Never Walk Alone" during a six-hour primetime broadcast scheduled for Sept. 4.
But MDA officials abruptly announced earlier this month that Lewis would no longer be the public face of the Tucson, Ariz.-based association without offering any explanation. When pressed by a reporter at the time about his role with the telethon, Lewis said: "It's none of your business."
Lewis has said he would hold a press conference the day after the telethon to clarify his plans. "I will have plenty to say about what I think is important. And that's the future, not the past," he has said.
The MDA announced major changes to its telethon Thursday, including slashing it down from a nearly 22-hour show to six hours of prime time television in an effort to boost audience numbers and raise more money.
The Sept. 4 show will be co-hosted by "American Idol" executive producer Nigel Lythgoe, "Entertainment Tonight" anchor Nancy O'Dell, "The Biggest Loser" host Alison Sweeney, and journalist and TV producer Jann Carl.