While clerking for Chief Justice Warren, Dyk came across a handwritten pro se petition for a writ of certiorari from a prisoner in Florida named Clarence Earl Gideon asserting that the trial court had improperly denied his constitutional right to a lawyer.

[3] The Supreme Court heard the case, and in March 1963 issued its landmark opinion in Gideon v. Wainwright, which established that the U.S. Constitution provides indigent defendants with the right to have the assistance of a lawyer.

Immediately prior to being nominated to the Federal Circuit in 1998, Dyk was a partner at Jones Day, specializing in First Amendment law.

[5] In an August 4, 1997, article in The Washington Post, Dyk was identified as one of "only a handful of repeat performers considered heavyweights" in representing clients before the United States Supreme Court.

Dyk's wife, Sally Katzen, was the Administrator of the Office of Information and Regulatory Affairs and the Deputy Director for Management, Office of Management and Budget during the Clinton administration, and is currently a Professor of Practice and Distinguished Scholar in Residence as well as the Co-Director of the Legislative and Regulatory Process Clinic at New York University School of Law.