Who Is David Weiss, the Prosecutor Overseeing the Hunter Biden Investigation?

The Hunter Biden case is an unexpected career turn for David C. Weiss, a tough, workmanlike prosecutor and commercial lawyer whose stubborn competitiveness earned him a reputation as a hard man to strike out in local softball leagues.

Appointed by President Donald J. Trump, the low-key U.S. attorney for Delaware was held over in his job by the Biden administration to shield the Justice Department from accusations of political meddling.

Mr. Weiss grew up in the Philadelphia suburbs, attending Cheltenham High School, whose graduates include Prime Minister Benjamin Netanyahu of Israel, the Hall of Fame slugger Reggie Jackson and the conservative commentator Mark Levin.

He graduated from Washington University in St. Louis. After completing law school at Widener University in Wilmington, Del., he worked two long stints as a prosecutor in the Delaware U.S. attorney’s office on an array of cases. Those included an investigation of a businessman who pleaded guilty to campaign finance violations after illegally bundling contributions for President Biden’s failed 2008 bid for the White House.

Mr. Weiss, graying and bespectacled now, once bore a striking resemblance to the singer Tony Orlando. In early 2018, when his colleagues celebrated him after his unanimous confirmation by the Senate, they did so against the backdrop of an old, blown-up photo from the 1970s of Mr. Weiss with long, center-parted hair.

He has been, until now, a noncontroversial figure, earning the support of both of Delaware’s Democratic senators when Mr. Trump, now a critic, nominated him in late 2017.

“David is a career prosecutor and dedicated public servant, longtime Delawarean and valued member of our law enforcement community,” Senator Chris Coons said in a statement at the time, according to The News Journal.

In announcing his nomination, Mr. Trump said in a statement that Mr. Weiss would “share the president’s vision for ‘Making America Safe Again.’”

People who know Mr. Weiss said that the Biden case, the best-known investigation he has overseen, is not what he believes will define his legacy.

In the late 1990s, while in private practice, Mr. Weiss began looking into the disappearance of Anne Marie Fahey, a secretary for Delaware’s governor — prodding his friends in the U.S. attorney’s office to join the local investigation, at the behest of Ms. Fahey’s family.

The trail eventually led to Thomas Capano, a former boyfriend of Ms. Fahey’s and a well-connected former Delaware deputy attorney general. He was convicted of murdering Ms. Fahey after their relationship ended and then dumping her body into the ocean.

“He would tell you that was his most important case,” said Thomas W. Ostrander, a lawyer who worked with Mr. Weiss for Ms. Fahey’s family. “We were in regular contact with them every day, for months and months, and David guided them through everything, because he was such an experienced trial lawyer and knew the pitfalls and challenges of putting together such a complex case.”