He credits Greitens and The Mission Continues with his transformation. “The fellowship helped me out with my confidence,” Smith says. “Now I want to be able to do the same for other veterans. To keep giving back. Because they have provided me with more than I can ever imagine.”

Before he was even out of college in 1996, Eric Greitens had volunteered in Bolivia, China, Rwanda and Bosnia. He helped people who were suffering — victims of abuse, genocide and war. He thought he was doing all he could until a woman confronted him on a train to Croatia. “Why isn’t America doing anything to [help]?” she asked.

Out of this experience came a philosophy of life that is at the heart of Greitens’ latest book: a combination of the heart and the fist. At its core, it’s a book about what it takes to live well.

“Think of it as the compassion that’s necessary to be loving and to be receptive to people who are hurting, and the courage that it takes to genuinely care for somebody else,” Greitens says.

It was this philosophy that led Greitens to the Navy SEALs. He had just graduated from Oxford, and a world of privilege beckoned. Instead, he remembered the angry woman on the train, and he listened to his heart and signed on for SEAL training at the age of 26. The training offered not only the greatest challenge of all (Greitens was among the 21 out of the original 220 trainees to graduate) but also the chance to live his values. He also wanted to serve his country. Eventually he would be wounded in Fallujah, Iraq, by a suicide truck bomb filled with chlorine gas. Luck was on his side that day, though. Despite some burns and a scalp full of concrete fragments, Greitens was able to return to active duty in 72 hours.

After his tour of duty ended, he went to the National Naval Medical Center in Bethesda, Md., to visit wounded veterans — and each soldier wanted to return to his or her unit. For most, though, that simply wasn’t an option. Greitens said he wanted to do something for these veterans.

“One of the great principles of military leadership is that you take care of your guys,” he says. “For me, that doesn’t end when you step off the battlefield. If I wasn’t going to do this for them, who would?” He knew there would be parades for these wounded warriors when they returned to their hometowns. They would get free gift baskets, cellphones, movie tickets and other material gifts. But then what? “What I didn’t find,” Greitens says, “was anybody who was giving veterans a challenge, who was actually going to them and saying, ‘We still need you … we don’t see you as problems. We see you as ­assets, and we want you to serve again.’ There is a powerful simplicity in our message: It’s not a charity; it’s a challenge.”

It’s also Greitens’ mission.