LAS VEGAS - The last great American heavyweight champion is finally hanging up his gloves.Evander Holyfield told SI.com he is retiring from boxing after a career that spanned nearly 30 years and a record four heavyweight title reigns. Holyfield will make a formal announcement Friday at a party celebrating his 50th birthday in Los Angeles."The game’s been good to me and I hope I’ve been good to the game,” an upbeat Holyfield said Monday from his Atlanta home. "I’m 50 years old (on Friday) and I’ve pretty much did everything that I wanted to do in boxing.”Many veteran observers will say the decision is long overdue. A little more than a decade ago, Holyfield was one of the most recognizable athletes on the planet, having generated more than a half-billion in pay-per-view receipts. Yet he won just eight of his last 18 fights. The New York State Athletic Commission banned him from boxing due to "diminishing skills” in 2005, forcing Holyfield’s more recent bouts to such inglorious outposts as White Sulphur Springs, W.Va., and Corpus Christi, Texas.He’d spent the past few years campaigning for a shot at Wladimir or Vitali Klitschko, the brothers who collectively rule the heavyweight division, with the goal of retiring as champion. But each Klitschko brother -- despite their mutual need for "name” opponents -- rebuffed Holyfield’s persistent overtures out of respect. ("He is my idol,” Vitali said in August. "I can’t do it for any amount of money.”)Holyfield’s dream of regaining the titles had been derided as quixotic. Yet when wasn’t Holyfield dogged by naysayers? Fact is, if Holyfield paid mind to his critics, his career would have never gotten off the ground -- let alone reached the stratospheric heights he occupied throughout most of the 1990s.There was never an off switch for the stubborn self-belief that propelled Holyfield, a blown-up light heavyweight who made overachievement his personal obsession. They said he couldn’t pack enough bulk on his undersized frame to contend at heavyweight. (Oops.) They were positive he was too small to win a title in a division ruled by Tyson. (Wrong again.) They feared for his life when he finally met Iron Mike in 1996 as an 18-to-1 underdog. (You were saying?)"Even at this old age I’m willing to fight the Klitschkos,” he maintained Monday. "I can beat the Klitschkos, but they didn’t want to do it. I can’t make nobody fight.”And so it’s over.Holyfield walks away with a record of 44 wins, 10 losses, two draws and one no-contest, with victories over Tyson (twice), Riddick Bowe, George Foreman, Larry Holmes, Michael Moorer and Ray Mercer. Nicknamed "The Real Deal,” the Georgia native held the lineal heavyweight championship in 1991-93 and 1994-95. He appeared on the cover of Sports Illustrated six times, more than any other fighter besides Muhammad Ali (38), Tyson (15), Sugar Ray Leonard (12), Sonny Liston (10), Marvin Hagler (nine), Roberto Duran (eight), Foreman and Joe Frazier (seven apiece).Still, Holyfield said his greatest memory remains being part of the U.S. Olympic team in 1984 that captured a record nine gold medals, with Holyfield settling for bronze due to a controversial disqualification.Holyfield won his first world title at cruiserweight in 1986 with the first of two memorable victories over Dwight Muhammad Qawi. Within two years, he’d consolidated the belts to reign as undisputed champion in a division of middling prestige, turning his sights on the heavyweight title held then by Tyson.He was ringside in Tokyo when Tyson lost the title in stunning fashion to James "Buster” Douglas in 1990. He destroyed Douglas to capture the undisputed championship later that year, defending it three times before a unanimous-decision loss to Bowe that elevated both men’s stature in the sport.