Immediately after graduating from law school, Professor Weninger began general practice. Four years later he entered a graduate program at the University of Chicago and completed an advanced law degree. He then accepted a position as a trial attorney with the National Labor Regulations Board of the 19th Region of the United States headquartered in Seattle. Professor Weninger served as a trial attorney for five years, with his work concentrating on the National Labor Relations Act. From there he became a trial attorney for the Federal Defenders Program in San Diego, where he served as trial attorney for two years before accepting a position as professor in the School of Law at California Western University in San Diego.

Since arriving at the Texas Tech School of Law, Professor Weninger has taught primarily in the areas of procedure, evidence, and litigation. He has pioneered the use of sociological data as a basis for critical analysis of the operation of the United States legal system. His publications have appeared in such national law journals as the Virginia Law Review, the UCLA Law Review, and the Southern California Law Review. Professor Weninger has been a visiting professor at Temple University School of Law.