During World War II, he served with the Royal Air Force, and was awarded the Distinguished Flying Cross (DFC) and bar for two tours as a navigator in anti-shipping strike squadrons.
Having assisted Ashton in choosing music for his Picnic at Tintagel for New York City Ballet in 1952, Irving helped the choreographer to surmount musical problems in the last act of his Sylvia in September the same year, by interpolating passages from the same composer's La source.
In 1956, in celebration of the 25th anniversary of the Vic-Wells, now the Royal Ballet, Irving arranged music by Alexander Glazunov for a "grand pas de quatorze" by Ashton, Birthday Offering.
[4] From 1958 to 1989, he served as music director of the New York City Ballet, where he worked extensively with choreographer George Balanchine.
[6] A small memorial plaque to him may be found on the north-east wall of Winchester College chapel cloisters.