[3] Wengert was employed in several positions by the Tennessee Valley Authority (1941–48); was a member of the Program Staff in the Office of the Secretary, U.S. Department of the Interior (1951–52); was a Research Associate for Resources for the Future (1956), and served as Deputy Director of the National Recreation Survey[4] of the Outdoor Recreation Resources Review Commission (1959–60), which provided the basis for Interior Secretary Stewart Udall's successful program for quadrupling the acreage of the National Park System in eight years, and for enactment of the Land and Water Conservation Fund Act of 1965,[5] providing money for recreational land acquisition.

During this period he also served as Visiting Research Professor at the U.S. Army Engineering Institute for Water Resources (1969–70), was a Summer Fellow at Fonds für Umweltstudien, in Bonn, Germany (1973), and lectured at the University of Sarajevo in 1978.

[14] Later in his career he advanced a seminal theory of the "politics of getting" in which he asserted: "American politicians will get as much as they can for their constituents, with only casual attention to the merits of the case and to the extent that they are not likely to be held directly accountable for costs".

[1] Recognition of his scholarship is evident in Wengert's invitation to testify as an expert witness on "Public Participation in Scientific and Technical Decision Making" during hearings before a subcommittee of the U.S. House of Representatives Committee on Science and Technology in 1977,[19] an uncommon honor for a university professor.

On that occasion, his 1976 Natural Resources Journal article "Citizen Participation: Practice in Search of a Theory"[20] was reprinted in the hearings record in its entirety, something that is also unusual for an academic.

[8] Wengert was Special Advisor to the Government of India on food and agriculture (1959); provided advice to the Federal Aviation Administration (1963); served as research consultant on environmental and natural resources issues for the School of Natural Resources, University of Michigan (1968–69); on environmental impact assessment of water projects for the U.S. Army Corps of Engineers (1968); with Thorne Ecological Institute (1972–75); Atlantic Richfield Oil Corporation (1973–74); the U.S. Department of the Interior's Office of Water Resources and Technology (1973–75); the National Water Quality Commission (1974–81); the Western Interstate Nuclear Board (1975–76) and for the states of Colorado, Maryland, Georgia, and Michigan on numerous occasions.