Greg is native of California. During World War II, Greg was assigned at Henderson Field in Guadalcanal under Captain Peterman and eventually joined up with Eddie Blake's military unit. Their mission was to map Japanese caves to be demolished. They were ambushed by a sniper and the fled straight into a minefield. Six of his team were killed, with their fireman falling on a mine. After a big explosion pushed Greg and Blake away, they blacked out. A native Soloman mother and her child who made their living as scavengers helped him on his feet and together they dragged Blake to their hideout where they were tended. When they were able to, Greg and Blake swam their way back to their base.