after graduating from yale, philbin attended harvard law school, graduating in 1913. after receiving his degree, he practiced for three years with a law firm in dallas, texas. in 1916, he joined the new york firm of fish, richardson & neave as a patent lawyer. he spent most of his career with that firm. during world war i, he served with the army signal corps in a unit commanded by fiorello la guardia in foggia, italy. during world war ii, while la guardia was mayor of new york, philbin served as the general counsel of the city's civil defense volunteer office.