1) Clark, John F. (John Frank, 1964- ), political scientist at Florida International University.
2) Clark, John F. (died 2012), former director of the Goddard Space Flight Center, 1965-1976.
3) Clark, John F. (John Franklin), public policy and energy policy expert in South Carolina and author of Scenic Driving South Carolina and Hiking South Carolina.
4) Clark, John F., author of Successful Service and the Co-operation of God.
5) Clark, J. F. M. (John F. M.) 1963- Bugs and the Victorians