(Haraz N. Ghanbari.ASSOCIATED PRESS)

For more than four years, he has signed letters of condolences. For more than four years, he has stared at the names of fallen soldiers.

“There’s probably not a day in the last four years that I haven’t wept, and it’s mostly when I’m doing those letters,” Gates said in an interview with the Associated Press.

Gates, whose last day in the job is Thursday, has always been deeply affected by those losses, perhaps more so than many of his predecessors. And as our colleague Greg Jaffe notes, the secretary has not been afraid to show a softer side.

It’s also true that Gates has done more than some of his predecessors to push resources to the battlefield in the face of bureaucratic resistance and opposition from the services. Until faced with pressure from Gates, the Army balked at the prospect of replacing Humvees with MRAP vehicles — which later proved crucial to limiting casualties among troops. The Air Force wasn’t much interested in deploying Predators to the war zones, until Gates assembled a team to help find more of them in the military’s arsenal.

Below is a photo essay produced by Reuters photographer Jason Reed during Gates’s final journey to Afghanistan as secretary. It’s a little artsy. It arguably leans a little toward the laudatory. But it also does a pretty good job of capturing Gates’s spirit, and his passion for the troops.

Staff researcher Julie Tate contributed to this report.