He served as Senior Fellow of Brookings Institution, and on Board of Governors of Yale University Press.
Wellington started teaching at Yale Law School in 1956 as an assistant professor.
He helped rebuild the faculty during his deanship, hiring over 30 professors,[7] including Anthony T. Kronman,[nb 1] Barbara Black, Drew Days, Paul Gewirtz, George Priest, Stephen L. Carter, Lucinda Finley, and Oliver Williamson.
[5] As Dean, he developed the Yale Law School's loan forgiveness program.
He was a Lifetime Honorary Member of the Yale Law School Executive Committee.
[11] In 2005, Yale Law School honored him by naming the Harry H. Wellington Dean's Discretionary Fund for Faculty Support after him.
[5] Under his deanship, the curriculum was revised to put greater emphasis on the practical skills of a professional attorney.