how many active duty army
U.S. Military Personnel 1954-2014. by David Coleman. Here are how the numbers of active duty military personnel have fluctuated over the past 60 years. The numbers for all services spiked in 1968-69 as U.S. involvement in the Vietnam War reached its peak. All dropped dramatically as that war drew down. But even the peak of the Vietnam War pales in comparison to World War II. In 1945, there were over 12 million active duty military personnel.