He received his BSc and MSc degrees from Tel-Aviv University (Thesis: Biology and ecology of caddisflies of Israel) and PhD degree from The University of Wisconsin, Madison, Wisconsin (Thesis: Input and importance of allochthonous organic matter in Lake Wingra, Madison, Wisconsin). After a post-doctoral position (Wisconsin Alumni Research Foundation: Role of littoral zones in lakes) he returned to Israel and joined the Institute for Nature Conservation Research of the Faculty of Life Sciences, Tel-Aviv University. Over the years Professor Gasith held several academic positions at Tel-Aviv University among them Head of the Institute for Nature Conservation Research; Head of the Department of Zoology; and founder and Head of the Environmental Studies Master Program, Porter School of Environmental Studies.