He first appeared when Virgil, Ash, and his friends were going to his office regarding the whereabouts of Davy. Jeff told him and the group that there was a situation regarding many Cryogonal at the dam. When Davy was trapped inside a building located there, Jeff wanted to go and rescue him, but Virgil told him to stay behind. In that case, he had Virgil and the group go to the dam and rescue him. He was last seen waving his farewells to Ash and the gang while they set off to Vertress City.
Jeff is likely based on Jeff Tracy from the 1960's TV series Thunderbirds, who is also the founder and leader of a rescue organization, with his sons doing the actual rescuing while he supervises and coordinates the rescue missions from the base.
In addition, Jeff's second-oldest son is named Virgil in the TV show as well.