Brendan Sullivan is a senior partner at the firm with nearly forty years of litigation experience in federal and state courts throughout the country. Mr. Sullivan is recognized nationally as one of the best known and most able trial lawyers in America, with an extraordinary record of successes. His principal areas of practice include all types of complex commercial litigation, including securities, antitrust, banking, RICO, and license disputes; the defense of major law firms in malpractice cases and the defense of accounting firms; products liability and mass tort; will contests; as well as high-profile criminal litigation. Typical clients include Fortune 500 companies involved in criminal investigations, litigation, or government regulatory matters.

In keeping with Williams & Connolly LLP's long tradition of representing individuals charged with white collar criminal violations, one area of Mr. Sullivan's national practice continues to be the defense of persons caught up in the high-profile case. Typical cases would be those of Lt. Col. Oliver North and former HUD Secretary Henry Cisneros. Both involved massive legal battles against large prosecutorial teams working at the direction of specially appointed "Independent Counsels" with unlimited resources. Recent cases include the successful defense of Dick Grasso, CEO of the New York Stock Exchange, in litigation brought by the Attorney General of New York. Also, Mr. Sullivan defended U.S. Senator Ted Stevens. The case was dismissed when Mr. Sullivan and his team uncovered that government corruption had infected the trial. Other cases have involved major federal investigations and prosecutions of corporations and their senior executives in industries such as defense, healthcare, food production and distribution, agriculture, international trade, finance, securities, banking, and manufacturing.

His peers and the media have repeatedly recognized Mr. Sullivan as one of today's most respected trial lawyers. ABC World News named him "Person of the Week" praising the manner in which he handled six days of televised congressional hearings in the Iran-Contra matter. A New York Times editorial attributed the subsequent courtroom victory to North's "battling lawyers." The Washington Post has described him as a "world class lawyer." The National Law Journal regularly lists him as among "America's One Hundred Most Influential Lawyers." The Legal Times listed him as the "Best Counsel Available" in Washington and identified him as "the leader" of the group. In 2006, Legal Times identified him as "The Leading Lawyer in White Collar Criminal Defense" as chosen by the D.C. legal community. The Washingtonian magazine called him "D.C.'s Toughest Lawyer" and in a survey of 500 leading lawyers in Washington, Mr. Sullivan was ranked "Number One" and was regarded as "unmatched in preparation, quick-wittedness and aggressiveness."

Mr. Sullivan lectures at various law schools and at continuing professional education programs. He is a principal speaker at various bar and judicial functions. He is the senior member of Williams & Connolly's Executive Committee.