Martland accepted the appointment of the first full-time paid pathologist at the Newark City Hospital in January 1909. When
World War I broke out, Martland joined the Bellevue Hospital Unit and as a lieutenant colonel he took charge of a hospital in Vichy, France. He later was awarded a Citation for Exceptionally Meritorious and Conspicuous Service by General
John Pershing. In June 1925, Martland was chosen to fill the post of Essex County Physician. He set out to establish the medical examiner system in Essex County. He was appointed Chief Medical Examiner by the Essex County Board of Freeholders. In April 1933, he was named Professor of Forensic Medicine at
New York University, a post he held for fifteen years. Martland made important contributions in the fields of pathology and forensic medicine. The work that attracted the most attention was his research begun in 1924, on the effects of radioactive material on the human body. Martland determined that minute traces of radioactivity contained in luminous paint had caused the deaths of watch dial painters employed at the US Radium Corporation in
Orange, NJ. The Atomic Energy Commission (AEC) credits Dr. Martland's work with having made it possible for atomic development to proceed with comparative safety. At the request of the AEC, Martland prepared a permanent exhibit on radioactive dangers and precautions which is on display in
Oak Ridge, Tennessee. In 1916, Martland alerted dynamite manufacturers to the dangers of occupational poisoning in TNT. It was Martland who proved, back in 1928, that "punch drunk" prize fighters were suffering from a brain injury caused by the rupture of blood vessels. He did notable work in phases of cardiac syphilis and in the effects of bullet wounds on the body. Martland's accomplishments also included the first paper establishing the lethal effects of beryllium poisoning, which led to implementation of regulatory reforms governing the use of beryllium in industrial plants. ==Honors==