[1][2] His family has a long tradition of military service, including his grandfather, Colonel Antonio M. Navas, who served in both World Wars.

His father, Captain William A. Navas Sr. served in World War II and had a successful career in civil engineering upon his retirement from the military.

[4] After graduating from high school, he enrolled in the University of Puerto Rico at Mayagüez, and received his Bachelor of Science degree in civil engineering.

[15] From June, 1998 until retiring from the military in October, 1998 Navas was a special assistant in the Office of the Vice Chief of Staff of the United States Army.

[16] On June 6, 2001, Navas was nominated by President George W. Bush to serve as the Assistant Secretary of the Navy (Manpower and Reserve Affairs).

[17][18] From 2008 to 2011 Navas served as executive director of the National Security Professional Development Integration Office at the United States Department of Defense, the first individual to hold this position.