Teaming with Joseph Clark in 1975, Mathews cofounded Mathews & Clark Communications, a high-technology public relations agency that quickly expanded to set up offices around the world. In 1976 Mathews & Clark became the public relations arm for SEMI. The agency played a major role in SEMI's growth and in establishing the Semicon trade shows. Mathews retired as CEO in 1999. The agency he cofounded changed its name to Positio Investor & Public Relations that same year.

"Walt's influence is still very much a part of Positio," said Stew Chalmers, the agency's current chairman and CEO. Dan Hutcheson, president of VLSI Research and a long-time associate, called Mathews "a master at PR," saying he "commanded a respect reserved only for industry statesmen, which he clearly was." Stan Myers, president and CEO of SEMI, also mourned Mathews's passing. "The entire SEMI family is reflecting warmly on a gracious and articulate gentleman who contributed so much, both personally and professionally."

A graduate of the University of Texas with a degree in journalism and broadcasting, the native of Dalhart, TX, had teamed with Clark early in his career to write comedy. Working in Los Angeles, the duo created scripts for television shows such as Love American Style and Carol Burnett Presents. Mathews also wrote nightclub material for Debbie Reynolds and Zsa Zsa Gabor. In 1959 he began his career in high-tech communications when he became editor of Electronic News.

Mathews is survived by his mother, Nina Mathews, and his brothers, Bill, Harry, and Phil. A memorial service was held March 2 at the Los Altos Lutheran Church in Los Altos, CA