Gary Bettenhausen led 138 laps until his car suffered ignition trouble on lap 176, and he coasted to the pits. Jerry Grant took over the lead but pitted for a new tire and fuel on lap 188 in teammate Bobby Unser’s pit - for which he would later be disqualified. Bettenhausen's Penske teammate Mark Donohue won the race, after leading only the final 13 laps. It would be owner Roger Penske's first of sixteen Indy 500 victories (as of 2015). Al Unser, Sr., who won the race in 1970 and 1971, was looking to become the first driver in history to "three-peat" at the Indianapolis 500. He fell short, but his second-place finish ties for the best three-year span (1st-1st-2nd) in Indy history.

On the morning of the race, track owner Tony Hulman asked Jim Nabors to sing "Back Home Again in Indiana" during the pre-race ceremonies. Nabors accepted and performed, without rehearsal. It was the beginning of a 36-year tradition, where Nabors performed nearly every year from 1972 to 2014.

The 1972 race was the first to utilize the Electro-PACER Light system to facilitate the yellow light periods. Speedway officials still did not utilize the pace car during cautions, and this enforcement tool would be used at Indy for seven years, albeit not without controversy in subsequent years.

After the decade of the 1960s saw numerous drivers from Europe and other nationalities, the 1972 race was the first since 1962 and the last to have an all-American lineup. Mario Andretti who was born in Istria (part of Italy at the time) was a naturalized U.S. citizen at the time of this race.

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Wikipedia