Joseph Hughes' silver medal was discovered by 11-year-old Finley Hargood who was magnet fishing in a Walsall canal, near the Birchills area of the borough.
Military records show Mr Hughes was a driver who served in the Royal Horse Artillery.
The medal in question is a British War Medal; awarded to all officers and men of the British and Imperial Forces in the First World War, who fought in battles or entered service overseas between August 5, 1914, and November 11, 1918.
About 6.5million of these medals were issued, mainly in silver but some in bronze.
Mr Hughes' medal was discovered in an old cigarette lighter box.
Finley's father Scott Hargood, 45, from Tipton, says Mr Hughes was highly decorated.
"He also got the George Cross," said Mr Hargood. "He got three in total so he was highly decorated. He served all over."
He continued: "The funny thing was, the medal wasn't in a presentation box, it was in an old fashioned cigarette lighter box.
"So that makes it a bit more different. Somebody has got to know who it belongs to.
"Me and Finley have found stuff before fishing and we have been able to return them to their owners.
"Something as valuable and as precious as this, we really want to do all we can to do that."
The magnetic fishing process is carried out by attaching a 200kg magnet onto the end of the rope and submerging it into water, such as canals.
Finley has unearthed other unique finds, including handguns and machetes. "You name it, we pull it out," he said.
Anybody who believes the medal may belong to their family is asked to email email@example.com.