Brendan Sullivan is a senior partner at the firm with forty-five 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, internal investigations, or government regulatory matters.

In keeping with Williams & Connolly'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.  Such cases include the representation 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.  In 2008-2009, Mr. Sullivan defended U.S. Senator Ted Stevens.  The case was dismissed when Mr. Sullivan and his team uncovered government misconduct that corrupted the trial.  In December 2009, a federal district court in California dismissed the options backdating indictment of Mr. Sullivan’s client, Dr. Henry Nicholas, the co-founder of Broadcom.  This case, too, was dismissed based upon misconduct of the government.  Though all cases vary and none is predictive, 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.  A major civil case includes the successful defense of Dick Grasso, CEO of the New York Stock Exchange, in litigation brought by the Attorney General of New York.

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." Benchmark Litigation listed Mr. Sullivan as one of the top 100 trial lawyers in America in the 2014 to 2016 editions of Benchmark’s Top 100 Trial Lawyers.  Chambers USA reported in their 2017 edition that he “enjoys an ironclad reputation as a white-collar specialist and trial maestro,” and quotes a source describing him as “one of the greatest lawyers ever.” In 2018, Chambers again recognized him as “a standout trail lawyers in the white-collar space” and a “tough, aggressive and tenacious” advocate for clients. In 2010, The National Law Journal listed Mr. Sullivan among “The Most Influential Lawyers of the Decade” (2000-2009) in litigation.  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."  In 2009, the Washingtonian listed him “Number One” again.  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.

Mr. Sullivan received the 2017 “Champion of Justice Award” from the Mid-Atlantic Innocence Project, an organization dedicated to fighting injustice in D.C., Maryland, and Virginia by bringing comprehensive legal assistance to individuals facing wrongful convictions and incarceration.

Born and raised in Rhode Island, Mr. Sullivan received his A.B. from Georgetown University in 1964 and his J.D. from Georgetown University Law Center.  He is a fellow in the American College of Trial Lawyers, and was awarded an honorary Doctor of Law by Georgetown University Law Center in 2011.  Mr. Sullivan served on the Williams & Connolly Executive Committee for 25 years.