Golfweek first reported the news and Golf Digest confirmed that Miller is stepping down following the Waste Management Phoenix Open in February.
"It just seemed like a nice round number,'' Miller told Golf Digest on Monday. "I've been on to 50 years with no break. I had my 24th grandchild yesterday. All my friends were retiring and it got to the point where I was like, 'Hey, how come I'm not retiring?' It's been a great run. I've done everything I can do announcing wise.''
Miller, 71, a member of the World Golf Hall of Fame, took over the analyst duties from Lee Trevino in 1990. The Phoenix event would be his one remaining tournament before NBC transitions to Azinger, who would also continue to work the U.S. Open and U.S. Women's Open for Fox Sports.
Azinger, 58, is a 12-time PGA Tour winner who worked alongside Mike Tirico and Nick Faldo when ABC did PGA Tour telecasts. He is also a former ESPN analyst.
Miller won 25 times in his PGA Tour career, including the 1973 U.S. Open at Oakmont and the 1976 Open at Royal Birkdale. In the final round of the '73 U.S. Open, Miller shot the first score of 63 in major championship history. Only Henrik Stenson at the 2016 Open has matched that score in the final round to win a major.
Retirement has been on Miller's mind for some time. His contract was extended through February of 2019, but he recently said at a media day for the Safeway Open that "It's been 50 years on the road, and part of me is saying 'that's enough.'"