The 24-year-old was fifth on Saturday with a time of 1:48.01 in a heat won by Nijel Amos of Botswana.
Only the top three went through automatically and English's time was not good enough for one of the fastest loser places.
His Ireland team-mate Brian Gregan did qualify for the semi-finals of the 400m as he secured third place in his heat.
Dubliner Gregan, 27, had a time of 45.37 seconds, just 0.11 outside the personal best of 45.26 he set at the Morton Games in Santry on 12 July.
"It played out as exactly as I wanted," said Gregan.
"I was ranked sixth going in on personal bests, and finished third so there is not much more you can ask than that.
"I did my own thing and it paid dividends."
Donegal athlete Mark English has missed out on a place in the 800m semi-finals at the World Championships in London.