Two years later, he accepted a position as a research associate with the Mississippi Agricultural and Forestry Experiment Station (MAFES) at MSU.

Senator Thad Cochran in Washington, D.C., from 1989–2006, first as a legislative assistant for agriculture and natural resources and then as chief of staff.

Keenum was named as the 19th president of Mississippi State University in November 2008 and began his term in January 2009.

He also represents the SEC as a member of the College Football Playoff's (CFP) Board of Managers.

[8] In 2018, Keenum was appointed as chair of the Board for International Food and Agricultural Development (BIFAD) by U.S. President Donald Trump.