He served in the British Army during World War II, where he specialized in designing camouflage for air bases and gun emplacements.
[2] After completing his military service, his mother gave him two days to find work in the theater before considering options, but Hall was able to find a job his first day looking for work as an assistant stage manager in a musical based on the opera Die Fledermaus, where he was able to make do in the wake of postwar shortages of materials.
While in New York City, he also designed costumes for the 1979 Broadway production of Zoot Suit.
[3] He dressed performers including Judi Dench, Plácido Domingo, Luciano Pavarotti, Joan Sutherland and Kiri Te Kanawa, and was noted by The New York Times for his costumes and "the way they moved, the way they caught the light, the way they could be coaxed amicably around singers of some dimension", with John Gage of the Dallas Opera describing how "his designs look like Renaissance paintings".
A gown he created for soprano Lella Cuberli in the Dallas Opera's production of Semiramide weighed 65 pounds and was constructed of scarlet covered with costume jewels, requiring four people on stage to control the 20-foot-long train he designed.