Raymond T. Odierno, a four-star Army general who was an influential architect of the surge of American forces during the Iraq war that helped quell sectarian killings and increase stability in the country, died on Friday. He was 67.

His death was confirmed by a spokesperson for the family, who said in a statement issued by the Army on Saturday that the cause was cancer and was not related to the coronavirus. Further details were not immediately available.

General Odierno also served as the Army chief of staff, the service’s senior officer, from 2011 to 2015. During that time, he reshaped the way many soldiers were trained and deployed, with some conventional units placed under Special Operations commanders and others assigned to regions of the world viewed as emerging security risks, like Africa.

General Odierno cut an intimidating figure, at 6 feet 5 inches and 250 pounds with a shaved head, but he was outgoing and popular with his troops. He served three tours of duty in Iraq from 2003 to 2010 and rose to become chief commander of all allied forces in the country.

He commanded the Fourth Infantry Division, which was involved in the capture of Saddam Hussein in northern Iraq in December 2003, in a mission that combined mechanized infantry units and the elite counterterrorism forces.

After U.S. Special Operations forces dragged the disheveled and heavily bearded Iraqi dictator from an underground hide-out on a sheep farm north of Baghdad, the general uttered one of the war’s most notable comments.

“He was in the bottom of a hole with no way to fight back,” General Odierno said. “He was caught like a rat.”

General Odierno returned to Iraq for a second tour of duty in 2006, this time as the Army’s second-ranking general. He returned with deep skepticism that the military strategy at the time would contain Iraq’s guerrilla insurgency and the escalating sectarian killings between Iraq Sunni and Shiite Muslims.

General Odierno favored the rapid deployment of about 20,000 additional troops — the surge, as it was called — to help quell the insurgency.

The troop reinforcement proposal split the military and was opposed by Defense Secretary Donald H. Rumsfeld. But Vice President Dick Cheney and the national security adviser, Stephen J. Hadley, backed it, as did Gen. Jack Keane, a former Army vice chief of staff who had the ear of influential White House officials.

By January 2007, President George W. Bush had approved the troop increase, fired Mr. Rumsfeld, and tapped Gen. David H. Petraeus as the new top commander in Iraq to carry out the new strategy, with General Odierno, the No. 2 general in Iraq, as the plan’s operational chief.

“Ray Odierno — the Big O to his many admirers, and I am among them — was a truly extraordinary leader, soldier, and human being,” General Petraeus said in an email on Saturday.

The surge was deemed a success at the time, as it dramatically reduced the sectarian killings and the war-shocked nation slowly started to stabilize. But military historians debate the strategy’s long-term effectiveness.

General Odierno received his fourth star, becoming a full general, in 2008, the year he replaced General Petraeus as chief commander of the multinational force in Iraq.

The war directly affected General Odierno’s family. His son, Anthony Odierno, a West Point graduate like his father, served as an infantry platoon leader with the First Cavalry Division in Baghdad. His vehicle was hit by a rocket-propelled grenade on Aug. 21, 2004, and he lost his left arm.

In September 2011, General Odierno was named the Army’s chief of staff, the service’s top general. He oversaw the final withdrawal of American troops from Iraq and confronted several other issues facing the military’s largest service, including troop cuts, suicides and reshaping the Army for a broader set of missions, including some in hot spots around the world where few soldiers had been deployed in the past. He retired from the Army in August 2015.

Raymond Thomas Odierno was born Sept. 8, 1954, in Rockaway Township, N.J., the grandson of Italian immigrants. His father was an Army sergeant during World War II.

After graduating from West Point in 1976, General Odierno became an artillery officer. He received a master’s degree in nuclear effects engineering from North Carolina State University in 1986 and a second master’s degree, in national security and strategic studies, from the Naval War College in 1990.

He served in the Persian Gulf War in 199l. During the administration of President George W. Bush, when he was a three-star general, he was the primary military adviser to Secretaries of State Colin L. Powell and Condoleezza Rice.

“He proved himself to be one of our most effective combat officers in the years after 9/11,” Mr. Powell said in a statement Saturday night.

General Odierno is survived by his wife of 45 years, the former Linda Burkarth; three children; a sister; and four grandchildren.