Dirk Pitt is the son of Senator George Pitt of California. With a woman named Summer Moran, he has twin children: a son, Dirk Pitt, Jr, and a daughter, Summer Pitt. He has had a long-term relationship with Congresswoman Loren Smith. He graduated from the United States Air Force Academy with lifelong best friend, Al Giordino. His weapon of choice is a .45 Colt that he received from his father.
In the course of his work as a marine engineer of the National Underwater and Marine Agency (NUMA), a oceanographic research organization head by Admiral James Sandecker, Dirk Pitt has made numerous important shipwreck discoveries as well as thwarted a large number of plans by villains intent on global catastrophe or world domination.