Sean received his Ph.D. in Psychology from the University of Washington in 1997 with a focus on unconscious/automatic cognition and computational methods under the direction of Tony Greenwald. Sean developed a psychological testing platform (Inquisit) as a graduate student in order to conduct his dissertation research. Upon completing his Ph.D., he worked with University of Washington Technology Transfer office to commercialize the software. He formed Millisecond Software LLC and began selling the product in 1999. Sean continued to develop Millisecond while working full time at Microsoft as a user interface researcher, software developer, and program manager in the Developer Tools division. At Microsoft, he helped design, release, and evangelize Visual Studio 6.0, Visual Studio .NET, Visual Studio 2003, and Visual Studio 2005. Sean left Microsoft in 2005 to focus full time on Millisecond.