Johnson was the first black partner at Paul Weiss. He was a litigation partner from 1994-1998 and 2001-2008, and an associate from 1984-1989 and 1992-1994. He began as an associate at Sullivan & Cromwell, 1982-1984.
He has left Paul Weiss three times for public service positions, only to return. He was an assistant U.S. attorney in the Southern District, 1989-1991, and general counsel of the U.S. Air Force, 1998-2001.
Born in New York City and raised in Wappingers Falls, N.Y., Johnson graduated from Columbia Law School in 1982 and earned his bachelor's degree from Morehouse College in 1979.
In a speech at Oxford University last week, Johnson said his job at the Defense Department is "to ensure that everything our military and our Defense Department do is consistent with U.S. and international law. This includes the prior legal review of every military operation that the secretary of defense and the president must approve."
He said that "it is the U.S. military's efforts against al-Qaida and associated forces that has demanded most of my time, generated much public legal commentary and presented for us what are perhaps the weightiest legal issues in national security," he said.
He added that in an unconventional conflict, "we apply conventional legal principlesconventional legal principles found in treaties and customary international law."
He defended the use of some controversial military practices by the Obama administration.
"Some legal scholars and commentators in our country brand the detention by the military of members of al-Qaida as 'indefinite detention without charges.' Some refer to targeted lethal force against known, identified individual members of al-Qaida as 'extrajudicial killing,'" he said.
Viewed within the context of criminal justice or law enforcement, "these characterizations might be understandable," he said in the speech. "Viewed within the context of conventional armed conflictas they should becapture, detention and lethal force are traditional practices as old as armies."
Johnson said he is a "student and disciple" of Martin Luther King Jr., "though I became an imperfect one the first time I gave legal approval for the use of military force."