Brown began his career in engineering before the outbreak of World War I and undertook an apprenticeship with British Westinghouse in Manchester. In 1914, he enlisted in the ranks of the University and Public Schools Brigade (UPS) for which he had to take out British citizenship. The ranks of the UPS were full of potential officers and Brown was one of those who sought a commission to become a Second Lieutenant in the 3rd (Special Reserve) Battalion of the Manchester Regiment. After service in France, Brown was seconded to 2 Squadron Royal Flying Corps as an observer.