Marion Michael Null was born in Brandinsville, Illinois, U.S, and married Nell Bernice Johnson in Chicago in June 1903. In September 1903, he visited Korea with his wife, a doctor, and handled medical missionary work centered on the missionary area of the North Presbyterian U.S.A.

Missionary Johnson, the first president of the Jejungwon, left for the United States in 1903 due to overwork, and the Null couple took charge of medical missionary work on behalf of the vacancy.

At that time, the hospital's facilities were insufficient, so only five patients could be hospitalized in a small ondol(Korean floor heating system) room, and if the number of people exceeded, they were allowed to get a room at a nearby inn to help treat patients. At the time, Null said, "I study languages in the morning and see patients who made reservations in the afternoon. It started at 2 o'clock and continues to watch until 7 o'clock. Even so, many patients return home without receiving treatment. We don't even have time to rest or breathe for a while. The work is heavy and our health is very poor." There was only one Western doctor in the vast area of the south of the Korean Peninsula, all the way to Busan. In the first year of his visit to Korea, the number of surgical patients treated by him alone reached 1,500.

Null accompanied his wife to Gyeongju with five Koreans to treat the sick, two of whom worked hard to preach all day as evangelists, and the remaining three were busy controlling and helping the patients. At first, only common people gathered, but after hearing the rumors, people of high status came to visit, and finally, the administrative head of Gyeongju invited him to the government office.

Null was transferred to the Cheongju area in 1907 due to the deterioration of his health, which eventually led to exhaustion as time went by. He also opened a reagent center in Cheongju to continue his career as a medical missionary.

On October 7, 1907, he resigned as a missionary and returned home with his wife, and on October 22, 1969, in Riverside County, California, he was called by God at the age of 97.

Marion Null's Tombstone