at the age of 21, brain was appointed to the first horn position in the national symphony orchestra. this tenure did not last long as he was soon conscripted into the armed forces with his brother in world war ii. both brothers joined the central band of the royal air force. when the royal air force symphony orchestra was formed, brain joined it. that ensemble went on a goodwill tour of the united states. during the tour, a number of orchestral conductors invited brain to join their groups after the war, including leopold stokowski of the philadelphia orchestra.