Giddens received all three of his degrees (BAE 1963, MSAE 1965, Ph.D. 1966) from Georgia Tech. He joined the Tech faculty in 1968, staying until 1992 when he left his position as the chair of aerospace engineering to serve as the dean of the Whiting School of Engineering and professor of mechanical engineering at The Johns Hopkins University. Giddens rejoined Tech in 1997 to establish the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University and served as the founding Chair until July 2002, when he became the dean of the College.

Giddens was elected to the National Academy of Engineering in 1999 for “contributions to the understanding of the ultrasound and fluid mechanics of arteriosclerosis and enhancing academic bioengineering education.”