He served as special counsel to an Atomic Energy Commission hearing that led to revocation of J. Robert Oppenheimer's security clearance in 1954.

He also successfully defended Otto Otepka, a former State Department official accused of giving unauthorized material to a Senate committee.

[2] Robb was special counsel to the Atomic Energy Commission at an AEC hearing on the loyalty of J. Robert Oppenheimer, the director of the Manhattan Project.

One observer commented that Robb "did not treat Oppenheimer as a witness in his own case, but as a person charged with high treason."

[4][5] Robb was nominated by President Richard Nixon on April 23, 1969, to a seat on the United States Court of Appeals for the District of Columbia Circuit vacated by Judge John A. Danaher.