Ralph Nicholson Ellis, Jr, was born June 15, 1908, in Jericho, near Oyster Bay, Long Island, New York to Ralph Nicholson Ellis, Sr. (1858-1930) and Elizabeth Warder Ellis. Ellis spent his childhood traveling between family estates on Long Island, Maine, and South Carolina. In 1920, Ellis moved with his mother to Berkeley, California, which became the family's primary home.

Ellis developed an interest in natural history at an early age; by the time he was 12 years old, he had a South Carolina license to collect birds' eggs and nests. At the age of 15, he became friends with several scientists at the University of California's Museum of Vertebrate Zoology, including E. Raymond Hall, the man who would later influence Ellis in bringing his expansive library to the University of Kansas. Ellis began to collect books on natural history in 1926. From 1926 on, he worked diligently to expand his library of natural history books, especially those pertaining to birds and mammals. At this point he also began subscribing to numerous journals, joined dozens of societies, and pieced together complete back files of periodicals. Ellis was so concerned that he might miss an important journal that eventually he was receiving over 200 journals regularly.

During a stay in London from 1936-1937, Ellis bought the greater part of the John Gould library, a collection almost forgotten in the Henry Sotheran, Ltd bookseller's basement. The collection held multiple copies of books, bound and unbound, plates in various states, manuscripts, and original lithograph stones. Ellis secured a large portion of the collection and returned with it to Berkeley.

In 1944, Ellis began to vigorously investigate the possibility of depositing his library at several institutions, from New York to California. His wife returned to Berkeley in early 1945 to pack up the collection. In February 1945, two freight cars loaded with the immense collection left for New York. A last-minute telegram stopped the cars en route and redirected them to Lawrence, Kansas. Professor E. Raymond Hall, who had befriended the young Ellis in Berkeley, was now the Director of the Museum of Natural History at the University of Kansas, and offered a home for the library. The books were safely housed, Ellis was given office space and access to laboratories, and a three-year contract was signed. In April 1945, papers were signed by Ellis that would pass ownership of the expansive library to the University of Kansas if he were to die during that three year interim.

Ellis died suddenly of pneumonia on a hunting trip near Colusa, California on December 17, 1945. The Ralph Ellis Library was passed to the University of Kansas, but only after a series of court trials. Ellis' widow contested the papers leaving the library to the University. The State Supreme Court decided in April 1950 that the books belonged to the University of Kansas.