McMahon died Tuesday after suffering bone cancer, but the cause of death was not immediately reported.
"For 30 years, a late-night ritual for millions began with Ed McMahon's booming voice introducing Johnny Carson," Jeff Zucker, NBC Universal's president and chief executive officer, said in a statement. "With Ed's passing, America has lost one of the greatest sidekicks in the history of the business, whose voice, along with his laughter and charm, added so much to the legacy of 'The Tonight Show.' Our thoughts and prayers are with Ed's wife, Pamela, and their family as we mourn the passing of an industry icon."
"Ed was full of life and joy and celebration," E! News quoted Doc Severinsen, McMahon's fellow "Tonight Show" veteran, as saying. "He will be sorely missed. He was one of the greats in show business, but most of all he was a gentleman. I miss my friend."
"Ed McMahon's voice at 11:30 was a signal that something great was about to happen," Letterman reflected. "Ed was a true broadcaster, and an integral part of Johnny Carson's 'Tonight Show.' We will miss him."
"Fifty years ago, Ed and I were next-door neighbors," Dick Clark recalled. "Over the years, our friendship grew while he became one of America's favorite television personalities. We were together for years. Ed was a big man, had big talent and a really big heart. We'll all miss him."
Drew Carey said via his Twitter page: "Cried over Ed McMahon this a.m. Started career 'Star Search/Tonight Show.' Ed there for both. Hope he had peace. Wonderful man."
Spears, also communicated her affection for McMahon, whom she met when she was a child competing on "Star Search."
"I am deeply saddened by today's news about Ed McMahon," Usmagazine.com said Spears Tweeted Tuesday. "He is responsible for giving so many artists their first shot, including myself. ... He was a wonderful man and will be greatly missed."