The Pentagon said Maj. Gen. Harold J. Greene was the highest-ranked American officer killed in combat in the nation's post-9/11 wars in Iraq and Afghanistan and the highest-ranked officer killed in combat since 1970 in the Vietnam War.
An engineer by training, Greene was on his first deployment to a war zone and was involved in preparing Afghan forces for the time when U.S.-coalition troops leave at the end of this year. He was the deputy commanding general, Combined Security Transition Command-Afghanistan.
The Pentagon's press secretary, Navy Rear Adm. John Kirby, said the attack occurred while the general and other officials were on a routine visit to an Afghan military academy at a base about 11 miles west of Kabul.
Early indications suggested the Afghan gunman who killed Greene was inside a building and fired indiscriminately from a window at the people gathered outside, U.S. officials said. There was no indication that Greene was specifically targeted.
The Army's top soldier, Gen. Ray Odierno, issued a statement Tuesday evening saying the Army's thoughts and prayers were with Greene's family as well as the families of those injured in the attack.
"These soldiers were professionals, committed to the mission," Odierno said. "It is their service and sacrifice that define us as an army. Our priority right now is to take care of the families, ensuring they have all the resources they need during this critical time."
In a 34-year Army career that began at Fort Polk, Louisiana, Greene, a native of Albany in upstate New York, earned a reputation as an inspiring leader with a sense of humility. He rose through the ranks as an expert in developing and fielding the Army's war materiel.
At the time of the Sept. 11, 2001, terrorist attacks Greene was serving at Fort Leonard Wood, Missouri, and when the U.S. invaded Iraq in March 2003 he was a student at the Army War College in Carlisle, Pennsylvania, at the rank of lieutenant colonel.
Greene flourished in the less glamorous side of the Army that develops, tests, builds and supplies soldiers with equipment and technology. That is a particularly difficult job during wartime, since unconventional or unanticipated battlefield challenges like roadside bombs in Iraq and Afghanistan, call for urgent improvements in equipment.
In 2009-2011, for example, he served as deputy commanding general of the Army's Research, Development and Engineering Command and senior commander of the Natick Soldier System Center at Aberdeen Proving Ground in Aberdeen, Maryland. During that tour of duty he gained the rank of brigadier general, and at his promotion ceremony in December 2009 he was lauded for his leadership skills and ability to inspire those around him.
Lt. Gen. Stephen Speakes applauded Greene for a "sense of self, a sense of humility" and an exemplary work ethic at the ceremony.
"In every job I had we got things done that I think made our Army better, and it was done by other people," Greene was quoted as saying at the time. "All I did was try to pull people in the right direction and they went out and did great things."
Greene and his wife, Susan, lived in the D.C. suburb of Falls Church, where neighbors recalled he would often go for morning runs. The Greenes' son Matthew also is in the Army and their daughter, Amelia, recently graduated from Binghamton University in New York.
Two stars hang in the Greenes' windowone for Maj. Gen. Greene and another for his son.
"It's just a shock and it's awful," neighbor and veteran Dave Swankin told ABC 7 News. "It's bad enough to be shot, even in the battlefield, but the way that happened, somebody pulled a gun that was supposed to be on his side. It's terrible."
Lt. Col. Juanita Chang, with U.S. Army Public Affairs, said she spoke Tuesday evening with Greene's widow Susan, who is also in the Army; two years ago at Fort Myer in Arlington, Virginia, she pinned two stars to her husband's shoulder at a promotion ceremony.
"The family has asked that I pass along that they believe that the Army, as well as Afghanistan and America, has lost a true hero today," Chang said. "He really believed in what he was doing over there, and was really proud to serve."
Greene earned a bachelor of science degree in materials engineering and a master's degree in industrial engineering, both from Rensselaer Polytechnic Institute in Troy, New York. He later studied at the University of Southern California and also attended the U.S. Army Command and General Staff College at Leavenworth, Kansas.
In 2010, he spoke at the opening of the Social Cognitive Networks Academic Research Center, a research facility at Rensselaer Polytechnic Institute with the mission of improving the Army's understanding of social, information and communication networks.
"We're in a fight now with an enemy that's a little bit different and uses different techniques ... and networks are a key part of that," Greene said at the event.
He said finding patterns in the tactics of insurgents was difficult because of the way networks evolve and otherwise change. So the goal was to bring to light the patterns and determine how to anticipate and influence the actions of insurgents.
"The enemy is every bit as good as we are at using that network to our detriment so this is essential work, this is about defending our country," Greene said. "You must know that there is a direct application on the battlefield and we're using it today, but we don't really understand it yet so this is a critical element."
His awards include the Legion of Merit, the Distinguished Service Medal, a Meritorious Service Award and an Army Commendation Medal.