4-minute milers tend to be young men in the prime of their life and 45% of all 4-minute miles have been run by men aged between 23 and 26-years-old. Roger Bannister was 25 when he ran the first 4-minute mile so the list of men who were the youngest when they did it is not going to be very long at all. Bannister (d.o.b. 23-Mar-1929) was 25 years and 44 days.
John Landy of Australia (d.o.b. 12-Apr-1930) was 24 years and 70 days old on 21-Jun-1954 when he ran his first at Turku in Finland. Láslzó Tábori of Hungary (d.o.b. 6-Jul-1931) ran his first on 28-May-1955 aged 23 years 326 days. he won that race, in which three men broke four minutes, the first time that had happened. in 2nd place (3:59.8) was Chris Chataway who famously helped pace Bannister to his momentous mile. less well known is that he also went to Finland to pace Landy for his world record and was now back in London pacing Tábori for his attempt. Chataway had therefore run in every race up to that point in which four minutes had been broken for the mile.
although not a world record time, Tábori did take the record for being the youngest 4-minute miler up to that point. but he held that record for less than a second because two places behind him in that race was Brian Hewson GBR (d.o.b. 4-Apr-1933) who ran 3:59.8 aged 22-years 54 days.
that record lastest just over a year, until 1-Jun-1956 when Ron Delaney of Eire (d.o.b. 6-Mar-1935) won a mile at Compton, CA in 3:59.0 aged 21-years 87 days. that was, incidentally, the fourth 4-minute mile run in the United States but none of them up to that point had been run by Americans. the first American to do so, Don Bowden (d.o.b. 8-Aug-1936), also took the record for the world's youngest sub-4 miler when on 1-Jun-1957 he won a mile at Stockton, CA in 3:58.7 aged 20-years 297 days. that remains the only sub-4 ever run in Stockton.
from the New World to the Antipodes, the record next passes to Melbourne, Australia where, on 25-Jan-1958 Herb Elliott AUS (d.o.b. 25-Feb-1938) won a mile in 3:59.9 aged 19-years 334 days. Elliott was the youngest sub-4 miler in the world for over six years and the youngest Australian for over twenty years when his record was broken by a young man who was not even born when Elliott set the record. Michael Hillardt AUS (d.o.b. 22-Jan-1961) won a mile in Adelaide, Australia in 3:59.0 on 14-Dec-1980 when he was aged just 19 years 327 days.
meanwhile, the world record passed back to the United States where it was once again broken by two men in the same race. at Compton, CA on 5-Jun-1964 eight men broke four minutes for the mile (the most in one race up to that point. the record today is 17 men under 4-minutes in Berlin on 26-Aug-1997) and all of them were Americans. the winner was Dyrol Burleson in 3:57.40 but he was 24-years-old and off to the Olympics where he finished 5th in the 1500 metres. behind him there was Tom O'Hara and Archie San Romani Jr, both in their twenties. Jim Grelle in 5th place was 27-years-old but less than half a second behind him was the new youngest sub-4 minute miler in the world.
Bob Day USA (d.o.b. 31-Oct-1944) ran the first of his 6 sub-4 miles at the age of 19 years 218 days. but he held that record for just one tenth of a second for two places behind him in 3:59.00 was Kanas schoolboy Jim Ryun (d.o.b. 29-Apr-1947) aged just 17 years and 37 days old. that remained the youngest that anyone (with a reliable date of birth) has run under four minutes for the mile for 53 years until a Norwegian schoolboy named Jakob Ingebrigtsen (d.o.b. 27-May-2017) ran 3:58.07 at Eugene, OR on 27-May-2017 aged just 16 years, 250 days. interestingly, Jakob finished 11th in that race and his own brother, Henrik, finished 3rd and I'm not aware of that happening before.
since I regard dates of birth in sub-Saharan Africa with what I think of as a healthy dose of suspicion I am loathe to get into debates about other 17-year-old sub-4 milers, but three men whose qualifications cannot be doubted are, in performance order: Marty Liquori USA (d.o.b. 11-Sep-1949) ran 3:59.80 in Bakersfield, CA on 23-Jun-1967 aged 17 years 285 days. Bennie Greyling RSA (d.o.b. 1-Feb-1965) ran 3:59.70 in Port Elizabeth, South Africa, on 23-Mar-1982 aged 17 years and 50 days. and Steve Cram GBR (d.o.b. 14-Oct-1960) ran 3:57.43 in London on 2-Jul-1978 aged 17 years 261 days. which, for the next few days at least, makes Cram the fastest 17-year-old miler in the world.
corrections and amendments always welcome.
cheers