He served in the U.S. military in World War II and developed the napalm fire bomb used in the Pacific Theatre.

[1] With America's entry into the First World War, Thomas was part of a group of men who believed the slogan that “Food Would Will the War.” Realizing that wheat would be an integral part of this strategy, Campbell presented a plan to the federal government that would use power equipment to cultivate mass acreages of semi-arid land.

He selected four large tracts of land on the Shoshone, Blackfoot, Fort Peck, and Crow Indian reservations in Montana and Wyoming.

[3][4] He acquired $2,000,000 financing from J.P. Morgan and began farming 200,000 acres (81,000 ha) on the Crow Indian Reservation north of the Big Horn River in Montana.

[3] The Thomas D. Campbell House, his childhood home, is listed on the U.S. National Register of Historic Places