Pearce, the England under-21 head coach, brought the famous old trophy with him as he visited troops on Saturday ahead of yesterday's FA Cup fourth-round draw.
He was visiting Camp Bastion, the main operating base in Helmand province.
Pearce, nicknamed "Psycho" in his playing days, told British Forces Broadcasting Services News (BFBS): "People bump into me and say, 'you represented your country'.
"But this is representing your country, being out here, putting yourself on the line for the greater good of others safe at home. That's humbling for me."
The 48-year-old coached at seven skills clinics and hosted two-hour long question-and-answer sessions.
He also oversaw a match on a dusty pitch with camouflage netting goals as Irish Guards and Afghan soldiers fought it out for the privilege of hoisting the FA Cup. The match ended in a 1-1 draw.
Warrant Officer Stephen Nadollek, a supporter of Pearce's former club Nottingham Forest, said: "It's a great privilege to be given the opportunity to meet and talk to him about life both as a player and manager.
"This has definitely been the highlight of my six-month tour."
A total of 349 UK military personnel have died since operations in Afghanistan began in 2001.
The visit came as it emerged a former Miss England, dubbed Combat Barbie, could be deployed to Afghanistan after completing her spell as a beauty queen.
Corporal Katrina Hodge, from Brighton, swapped active service for the glitz and glamour of the catwalk when she took the title last January.
The married soldier, decorated for her bravery in Basra, insisted she was glad to be back in the forces and ready to take on the challenge.
"At the end of the day, it's my job," she said.