Greg joined the Department of Economics at the University of Manitoba in 1974. From 1981 to 1986, Greg directed the Institute for Social and Economic Research at the University of Manitoba, where he was responsible for over $2.5 million of research, including the Mincome Manitoba experimental data. During this time, he also edited the Western Economic Review and published many research monographs. From 1986 to 1988, he directed the Social Sciences Division of University of Manitoba Research Ltd., which focussed primarily on contract research for government. Greg has been on the faculty of the Department of Economics since 1974 (tenured in 1975) and continues to hold a reduced appointment, teaching econometrics and program evaluation at the graduate level.

In 1988 he founded PRA Inc. with Rita Gunn and Kerry Dangerfield, which has grown to be one of Canada’s largest program evaluation firms.