Bellomo was a career officer in the Italian Army from the regular class of the Italian Military Academy of Modena. At the outbreak of World War I, he held the rank of Artillery Captain and during that war he was awarded the Italian Military Order for gallantry in action. He gave up active duty in 1936, but was reactivated in 1941, when he was assigned as commander of the XII MVSN Zone, and Bari province.