Marshall Yaap represents clients in domestic and international family law matters. His practice focuses on child custody, child support, divorce, property division, alimony, domestic violence cases, marital and premarital contracts, jurisdictional disputes under the Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA), and cases brought pursuant to the Convention of 25 October 1980 on the Civil Aspects of International Child Abduction. Mr. Yaap also represents clients in guardianship and conservatorship matters for children and adults. Additionally, Mr. Yaap represents clients in peace order matters, anti-stalking cases, and civil restraining orders.

Before entering private practice, Mr. Yaap served as a judicial law clerk at the Superior Court of the District of Columbia for retired Judge Odessa F. Vincent, Magistrate Judge Errol R. Arthur, and retired Magistrate Judge S. Pamela Gray. Prior to law school, Mr. Yaap worked for daily newspapers as a reporter and editor.