He attended Hamilton High School in Los Angeles, California, where he was an American football and baseball player. He later attended Arizona State University, where he majored in radio and television and minored in journalism.
He began his sports broadcasting career in Hawaii in 1968, calling the games of the Hawaii Islanders baseball team in the Pacific Coast League. He also called the play-by-play for the University of Hawaii's American football and basketball teams, and was named Hawaii's "Sportscaster of the Year" in 1969. In 1971, he moved to Cincinnati, Ohio, where he became the number one broadcaster for the Cincinnati Reds of Major League Baseball. He covered the World Series in 1972 for the NBC network. In 1974 he moved on to a similar position with the San Francisco Giants of MLB, and also covered basketball for UCLA before signing with ABC in 1977. Since then, he has covered a wide variety of sports in addition to those he established his career upon, including ice hockey, track and field events, figure skating, and many events of the Olympic Games. His current and longest-running assignment is that of the main sportscaster for the ABC television show Monday Night Football, which he has held since 1986.
Michaels has won numerous awards during his career, including the Emmy Award for Outstanding Sports Personality (Play-by-Play Host) four times, the NSSA Award from the National Sportscasters and Sportswriters Association three times (he was also inducted into their Hall of Fame in 1998), and "Sportscaster of the Year" once each from the American Sportscasters Association and the Washington Journalism Review.
Two of Michaels' more famous broadcasts were of the 1980 Winter Olympics ice hockey semi-final match between the United States and the Soviet Union, and the attempted third game of the 1989 World Series.
In 1980, an unheralded group of amateur ice hockey players from the United States won the Gold Medal at the Olympic Winter Games. The semi-final match on February 22, which assured the team of at least a Silver Medal, was of particular interest, as it was played against a heavily favored squad from the Soviet Union, and was in front of a partisan American crowd in Lake Placid, New York whipped into a patriotic fervor by the Cold War. Michaels' memorable broadcast of this game, including his interjection - "Do you believe in miracles? Yes!" - as time expired on the 4-3 U.S. victory, earned the game the media nickname of "The Miracle on Ice".
On October 17, 1989, Michaels was in San Francisco, California, preparing to cover the third game of the World Series between the home team, the Giants, and the visiting Oakland Athletics. While his broadcast partner, Tim McCarver, was assessing the Giants' chances for victory in the game, the Loma Prieta earthquake struck. McCarver fell into a stunned silence, but Michaels astutely said into the microphone, "I'll tell you what, we're having an earth--!" just as it went dead, providing the only concurrent broadcast account of what had happened. Audio was restored minutes later, and Michaels gave an eyewitness account of the aftermath at Candlestick Park, the Giants' stadium, for which he later won an Emmy Award for news broadcasting, becoming only the second sportscaster ever to win the award.
He currently lives in Los Angeles, California.