Todman was born on Saint Thomas, U.S. Virgin Islands, on March 13, 1926. His mother worked as a house maid and laundress, and his father was a grocery clerk. His childhood in St. Thomas would prove influential in his decision to become a diplomat. He later spoke of his school years as such: "...we found ourselves doing studies on different countries, obviously at a high school level, but nevertheless you got exposed to the fact that there were other places, other people, other things happening. So, with the movement of people in and out and with that kind of intellectual academic preparation, it made for a consciousness of a world outside and of the need to deal with other people."^[2] He graduated Charlotte Amalie High School second in his class.

Todman graduated from the Interamerican University of Puerto Rico summa cum laude. He was drafted by the United States Army while in college and served in Japan from 1945 to 1949.^[3] Todman earned an M.P.A. degree from the Maxwell Graduate School of Citizenship and Public Affairs at Syracuse University in 1952; the top-ranked and most prestigious graduate school of public administration.^[4] After passing the Federal Entry Exam, Todman received offers from the Office of Management and Budget, the Office of Personnel Management, the Bureau of Indian Affairs and the State Department. He joined the State Department and, the following year, passed the Foreign Service Examination.^[5]

During his Ambassadorship in Guinea, his embassy was under eavesdropping of the Soviet Union's KGB.^[6] His appointment as ambassador to Costa Rica in 1974 represented the first African American to be given the title in a Spanish-speaking country.^[7]

Todman was a member of Alpha Phi Alpha fraternity.^[8] He was also a director of Exxcel Group.^[4] The cafeteria at the Harry S Truman Building was named after Todman in 2022.^[9]

Todman was fluent in Spanish, French, Arabic, Hindi, and Japanese.^[10] He married Doris Weston; they had four children.^[3] On August 13, 2014, Todman died at the age of 88, at a hospital in Saint Thomas.^[11]