Clarence Cottam served as Foundation Director from 1955 through 1973. He was selected as the first director of the Welder Wildlife Foundation by the original trustees because of his national and international recognition as one of the leading conservationists of the day. Dr. Cottam was, indeed, one of the imminent conservationists of the early conservation movement. Most of his career was spent with the U.S. Biological Survey and the U.S. Fish and Wildlife Service (USFWS). When hired as the Foundation’s director, he was assistant chief of the USFWS. He had previously accepted the position of Dean of the College of Agriculture at Brigham Young University, so he spent one year at that institution prior to moving to the Welder Wildlife Refuge. The trustees wanted an individual at the helm who would give the Foundation immediate recognition and Dr. Cottam provided the Foundation with these qualifications.

Dr. Cottam spent much of his time in Washington, D.C. attending conferences and telling the conservation community about the newly created Rob & Bessie Welder Wildlife Foundation in the midst of a mesquite grassland in south Texas. He had many friends in the Washington area who were imminent in the early conservation movement. To build the Foundation's library, Dr. Cottam asked many friends who had extensive personal libraries to remember the Welder Foundation in their wills. Consequently, the Foundation’s library has one of the finest collections of wildlife literature in the nation. The largest contribution was that of Dr. Alexander Wetmore, a contribution of approximately 5,000 volumes. Other significant contributions include those of Dr. T. S. Palmer, Dr. L. L. Baumgartner, C. R. Gutermuth, J. S. Wade, Dr. A. L. Nelson, and Cottam’s own personal library.

Dr. Cottam also knew a budding museum specialist, Francis L. Jaques. In the construction and design of the Foundation's small museum, Cottam was able to persuade Jaques to design and build the first three-panel, three-dimensional murals that he had ever painted, although he had been doing two-panel, three-dimensional murals for some time. Thus, the Welder Wildlife Foundation owns the only three-panel, three-dimensional paintings ever constructed by Jaques, and these are now on display in the Foundation’s museum.

Under Dr. Cottam's supervision, construction of the Foundation’s headquarters buildings was initiated in 1958. The buildings, roads, and other facilities were completed and a formal opening was held in 1961.

Dr. Cottam’s persona can best be described as that of contagious enthusiasm. He was always ready to confront controversial conservation issues, particularly those involving the public interest, and he expended much energy, time, and personal finances helping students and young people through problem periods. He never spared himself when faced with requests for assistance on behalf of conservation issues. He frequently expressed his political philosophy that "Democrats and Republicans are the primary threats to our wildlife resources".

Dr. Cottam had a positive and jovial attitude and was a caring and respectful of his fellow man. He served as director of the Foundation until he passed away in 1973.