BBC World Service | National Park Service | Internal Revenue Service | Distinguished Service Order | Special Air Service | United Parcel Service | Meritorious Service Medal (United States) | United States Postal Service | National Health Service | National Film Board of Canada | Meritorious Service Medal | Metropolitan Police Service | United States Forest Service | German Academic Exchange Service | Board of directors | Secret Intelligence Service | Brown v. Board of Education | Immigration and Naturalization Service | Distinguished Service Cross | Board of Directors | board game | National Defense Service Medal | National Service | board of directors | United States Secret Service | Royal Naval Air Service | National Weather Service | Agricultural Research Service | Special Broadcasting Service | Distinguished Service Cross (United States) |
He was widely sought as a consultant and advisor to the Massachusetts General Hospital, the Veterans Administration, the National Research Council, and during World War II, the Selective Service Board.
Beginning in 1917, Clark managed the Selective Service Board for the northern district of Stark County during World War I.
Jenkins served in other leadership roles with the Mobile-Baldwin Area Boy Scouts of America, the Baldwin County Mental Health Board, the Baldwin County Executive Committee, and the Alabama Selective Service Board.