The 40-year-old left-hander struck out 13 and went to three balls on just one hitter — Johnny Estrada in the second inning. Estrada fouled off three straight 3-2 pitches before going down swinging.
It was the 17th perfect game in major league history, the 15th since the modern era began in 1900 and the first since the New York Yankees' David Cone against Montreal on July 18, 1999.
Cy Young, then 37, had been the oldest to throw a perfect game, doing it in 1904.
It was the second no-hitter of Johnson's career. The other was for Seattle against Detroit on June 2, 1990