Hullar is the Director of the Higher Education Program for Atlantic Philanthropies USA, Inc. He was Chancellor of the University of California, Davis and Riverside; Professor of Environmental Toxicology and Biochemistry, respectively; and also Director of the Economic Development Initiative for the University of California's Office of the President. Hullar chaired the Board on Agriculture for the National Research Council; is a past member of the Board and Executive Committee of the National Association of State Universities and Land-Grant Colleges; and was the initiator and coordinator of the National Water Initiative. He most recently served as Professor and Director of the Center for the Environment at Cornell University and earlier served as Director of Cornell's Agricultural Experiment Station. He was a founding member of the California Council on Science and Technology and served as the Council's first chair. He is a Fellow of the American Association for the Advancement of Science.