His professional career started at General Motors, where he worked in the area of computer-aided graphics and design soon after graduate school in early 1970s.
In the 1980s, he was a member of the founding team who conceptualized and developed the core concepts for what is today’s William R. Wiley Environmental and Molecular Sciences Laboratory, a DOE scientific user facility located at PNNL.
In the early 2000s, Thomas led and coordinated a team to formally define a new research area, visual analytics.
The U.S. Department of Homeland Security (DHS) established the National Visualization and Analytics Center (NVAC) at PNNL in 2004, naming Thomas as its founding director.
[4] He helped found the IEEE Visual Analytics Science and Technology (VAST) Symposium that began in 2006.