In 1981, Mr. Williams returned to California and was admitted to the California Bar to be the Director of Litigation of a legal services program in Fresno. There, he litigated cases involving farm worker access to health care, equal access to public services by racial and ethnic minorities, employment, and economic development projects for low income persons. He subsequently established his own law firm emphasizing employment and civil rights actions. He was active in community groups, including long service as chair of the board of directors of a non-profit child abuse prevention and treatment group. Mr. Williams began an affiliation with his current partners in 1997, working on select Indian law employment and litigation matters.

Mr. Williams has an extensive background in complex litigation. In addition to representing Indian tribes and tribal organizations in litigation, he also provides ongoing advice and consultation on employment and personnel issues, on natural resources, and on governmental and corporate affairs. Illustrative cases include representation of healthier tribal interests in employment disputes throughout the country, health clinics in personnel and organizational matters, water rights disputes, protection of tribal land and cultural sites from environmental degradation, and defense of tribal sovereign immunity in tribal, state and federal courts. 

Along with his partner, Curtis Berkey, and Professor Philip P. Frickey, Mr. Williams teaches the Advanced Indian Law seminar at Boalt Hall School of Law, at the University of California, Berkeley.