Kenneth Geller is Vice Chairman of the firm and a leading member of the Supreme Court & Appellate practice. Described by Chambers USA (2006) as ". . . 'a standout lawyer in a very talented group' . . . 'extremely experienced and seasoned, with superb judgment,'" Ken has written or edited some 300 briefs and certiorari petitions and argued more than 40 cases before the US Supreme Court. Most recently, he was described by Chambers USA (2007) as ". . . 'both incredibly organized and wonderfully clear. He is superb when you need someone to take a highly complex area of law and distill it to its essence.'"

In 2007, Ken was listed among The Best Lawyers in America in the area of Appellate Law. Chambers USA (2004) named him to the top band of its America's Leading Lawyers for Business list, noting that "Ken Geller has over 40 Supreme Court arguments under his belt, many of them for household names such as Ford, Chrysler and GM. 'Never less than immaculately prepared,' reported market observers, his is a familiar face in the highest courts, where he acts on cases of the ilk of American Insurance Association v Garamendi and National Park Hospitality Association v US DOI." In 1983, Ken received the Presidential Award for Distinguished Service in the field of law.

Ken joined Mayer Brown in 1986 and was named Vice Chairman of the firm in 2007. He was Partner-in-Charge of Mayer Brown's Washington, DC office between 1995 and 2007, and has been a member of the firm's Management Committee since 1995. Prior to joining the firm, Ken served as Deputy Solicitor General of the US Department of Justice (1979-1986) and as Assistant to the DOJ's Solicitor General (1975-1979). Between 1973 and 1975, he worked as Assistant Special Prosecutor for the federal government's Watergate Special Prosecution Force. Previously, he worked with a law firm in New York and, between 1971 and 1972, served as Law Clerk to The Honorable Walter R. Mansfield, US Court of Appeals for the Second Circuit.