The previous record was held by Moroccan Hicham El Guerrouj, who ran the distance - approximately 1,600 metres - in 3:43.13 in Rome in 1999. Kerr broke it with a superb run in front of the home crowd at London Stadium.
Second place at the Diamond League meeting went to American Yared Nuguse in 3:45.69.
The mile is not included in championship programmes, but has high status in the athletics world, according to AP.
Josh Kerr won silver in the 1,500 metres at the 2024 Paris Olympics.
