Rice was a reference assistant in the Ohio State University Library from 1911-1913. During this time, he helped move the a library from Orton Hall into a new building. He worked as a reference assistant at the New York Public Library from 1914-1917 and served as treasurer of the New York Library Association from 1916-1917. He served in the United States Army during WWI, rising from Private to Second Lieutenant. He was a lecturer in the New York Library School from 1919-1920, before becoming Chief of the NYPL Accessions Division in 1920. He served as Chief of the NYPL Preparation Division from 1920-1927. He was treasurer of the New York Library Club in 1922. He was president of the Dayton Public Library from 1927-1936. He was the First Vice President of the New York State Library School Association in 1928. He served as President of the Ohio Library Association from 1930-31 and chairman of its legislative committee from 1931-1935. In 1935, he received an honorary Master of Arts from Wesleyan University. During his tenure in Dayton, he confronted funding challenges as a result of the Great Depression. He also corresponded with W. E. B. Dubois regarding his magazine, The Crisis. He was posthumously elected into the Ohio Library Hall of Fame in 1980. Rice returned to New York to serve as the first Director of the New York University Libraries in 1936. He wrote a history of the Eclectic Society for its centennial in 1937. In 1938, Rice returned to the New York Public Library, to serve as the Director of the Reference Department. During this time he served as President of the New York Library Association from 1939-1940, Executive Secretary of the Association of Research Libraries from 1942–46 and President of the American Library Association from 1947-48. He was also an instructor at the Columbia University School of Library Service, and a fellow of the American Library Institute. Rice was involved with the Farmington Plan during World War II, working with Waldo Gifford Leland, Archibald MacLeish, Milton E. Lord and Keyes Metcalf. He was also in charge of securing rare books in the event of an air raid at the New York Public library. Rice corresponded with novelist Frederic Dannay, creator of the Ellery Queen pseudonym. He also corresponded with an Italian prisoner of war, held in New York, who requested the text of the Geneva Convention. Rice also corresponded with accused spy Philip Keeney, expressing disapproval of his actions. He wrote "I have no sympathy with any censorship of books in a college library which stress a different point of view than that of the administration, but neither have I sympathy, and I assume that with this you will concur, with using a college library for propaganda." He supported the efforts of UNESCO. In a speech as President of the ALA, Rice spoke of the role of libraries in a Cold War context: "our libraries are one force that assures that the United States can never succumb to fascism or any other kind of totalitarianism, we should do everything we can to influence UNESCO to stimulate such libraries everywhere." He was described by The New York Times as a "Foe of Censorship due to his defense of intellectual freedom during the Cold War." In New York, he was a member of the Rotary Club, the New-York Historical Society, and the Huguenot Yacht Club in New Rochelle. After retiring from the New York Public Library, he served as the Caleb T. Winchester Librarian and Director of the Wesleyan University Library from 1953 to 1956, and in the latter year was elected librarian-emeritus. He was active in the First Methodist Church, Middletown and the Middletown Rotary Club. He served as a trustee of the Russell Library in Middletown from 1954-1964. He was the editor of the 9th edition of the Wesleyan University Alumni Record, 1961.