[1][2] In 1952,[1] Crosby graduated from Harvard University, with a degree in history, then entered the U.S. Army in 1952,[3] during the Korean War, later spending (circa) twenty months stationed in the Panama Canal Zone,[4] in Latin America.
[1] After being discharged from the U.S. Army in 1955,[1] he obtained a master's degree in teaching from Harvard in 1956, and a doctorate in history from Boston University in 1961.
[5] Crosby was an inter-disciplinary researcher who combined the fields of history, geography, biology and medicine.
[5] According to Hal Rothman, a professor of History at the University of Nevada, Las Vegas, Crosby "added biology to the process of human exploration, coming up with explanations for events as diverse as Cortés' conquest of the Aztec Empire and the fall of the Inca empire that made vital use of the physical essence of humanity.
He retired from the chair of Professor Emeritus of History, Geography, and American Studies of the University of Texas at Austin, after teaching for 22 years, in 1999.
He traveled with thirty-six students to Delano, California to assist in building a health center for the United Farm Workers.