Professor Williamson received a Bachelor of Electrical Engineering from the Queensland University of Technology in 1984 and a Masters of Engineering Science (Electrical Engineering) from the University of Queensland in 1986. In 1990 he obtained a PhD in Electrical Engineering from the University of Queensland.

He joined the Australian National University as a postdoctoral fellow in the Department of Systems Engineering in 1990 and held a series of appointments before becoming a professor and head of the Computer Sciences Laboratory, Research School of Information Sciences and Engineering at the Australian National University.

From 2003 to early 2006 Professor Williamson was the Director of NICTA’s Canberra Research Laboratory. In 2006 he was appointed as NICTA's Scientific Director.

He is an advisory board member of the Australian Communications Research Network, a member of the advisory board of the National Institute of Informatics (Japan) and the Scientific Advisory Board of the Max-Planck Institute for Biological Cybernetics.

His scientific interests include signal processing and machine learning.