Bohun was born probably in England between 1575 and 1585. An acquaintance later wrote that Bohun had been “a long time brought up amongst the most learned Surgeons, and Physitions in Netherlands.” Most likely he received his medical education at Leiden, but nothing of his youth or education is definitely known.
Bohun, whose surname contemporaries often spelled “Bohune” or “Boone,” sailed for Virginia on April 1, 1610, as personal physician to the new governor,. Within a month after they arrived in on June 10, 1610, Bohun had treated the governor’s fever with bloodletting, which De La Warr believed had saved his life. Bohun soon depleted his medical chest treating colonists’ frequent illnesses, and during the nine and one-half months he was in the colony he experimented with indigenous native plants and minerals to ascertain their medicinal properties. He used sassafras to purge phlegm, employed a white clay to fight fevers, used the saps of gum trees and white poplar to make a balm for healing wounds, and compounded a medicine for dysentery from myrtle fruit.
Bohun left Virginia with De La Warr on March 28, 1611, bound for Nevis in the West Indies, where the governor hoped to recover from scurvy. The wind drove their ship instead to the Azores, where De La Warr decided to sail to England and recuperate fully before returning to the colony. Bohun found himself back in England a year after he had first arrived in Virginia.
On March 12, 1612, Bohun was one of 325 shareholders named in the third charter of the Virginia Company of London. During the next several years he probably practiced medicine among the court favorites and commercial leaders of London, and his marriage to Alice Barnes, widow of merchant William Barnes, of Lambeth, Surrey County, likely also occurred about this time. She had at least one son and two daughters before her marriage to Bohun, with whom she had one daughter.
Bohun continued his involvement in the affairs of the Virginia Company. In February 1620 he and James Swift were granted a tract of Virginia land for having transported 300 colonists and some cattle to Virginia. In November of that year the company approved Bohun’s request that the grant be renewed in his name only, and about the same time he subscribed to a petition that a suitable gentleman of quality be sent to Virginia as governor. The surviving records of the Virginia Company include two veiled references to a “project” of Bohun, which “promised much benefitt but in the end came to nothinge.” The scheme probably involved the cultivation of silkworms in Virginia. Bohun enjoyed a long friendship with members of the Ferrar family, who attempted to introduce silk culture in Virginia, and when Bohun sailed for Virginia the second time, he was on a ship transporting silkworm larvae, or “seed,” to the colony.
On December 13, 1620, the Virginia Company appointed Bohun physician general of the colony, a position that carried with it an allotment of 500 acres and twenty tenants to work it. The company also appointed him to the Council. Bohun and his stepson, Edward Barnes, embarked on the Margaret and John, of which Bohun was part owner, near the end of January 1621. When the ship arrived in the West Indies to take on fresh water, two Spanish warships attacked it. During the two-day battle the English drove off the larger Spanish ships, but the silkworm larvae were destroyed, and ten Englishmen were killed or mortally wounded, including Bohun, who fell with his pistol in his hand on March 19, 1621.