He attended Trinity Hall Military Academy[5] and Washington & Jefferson College,[6] both in Washington, Pennsylvania, and obtained his Bachelor of Arts in 1889 from Johns Hopkins University and his PhD in Medicine in 1892 from the Medical School at the Columbia University College of Physicians and Surgeons.

[7] Lazear was a physician at the Johns Hopkins Hospital in Baltimore starting in 1895, where he studied malaria and yellow fever.

In 1900 he reported for duty as the assistant surgeon at Columbia Barracks (Quemados, Cuba) for the United States Army.

The fact that this was a deliberate act was covered up at the time—for reasons unknown, but possibly connected with family insurance policies—and the story put about that Lazear had mistaken the mosquito for an uninfected one of a different species.

[9] A dormitory at Johns Hopkins University was named after him in honor of his sacrifice, as was a former chemistry building at Washington & Jefferson College, Lazear's alma mater.