Jeff Angelo was the grandson of Mrs. Angelo, a friend of Amy Pond and a resident of Leadworth.
Jeff apparently lived with his grandmother. In 2008, the newly regenerated Eleventh Doctor convinced him to send a virus from his laptop to various alien experts, transmitting it across the world to bring Prisoner Zero to the Atraxi's attention. He was praised as a hero by the Doctor, who told Jeff that at least one of the alien experts would offer him a job. When Jeff asked why he was chosen by the Doctor, the Doctor replied that it was because it was his bedroom. (TV: The Eleventh Hour)
Later, when Amy Pond was telling the Doctor that she was to be married, the Doctor asked if it was to "the good looking one", referencing Jeff, before Amy told him that it was Rory Williams. (TV: Flesh and Stone)
In the alternate reality in which every moment in time began to happen at once, Amy remembered events by drawing pictures, but had trouble remembering Rory; when asked by the Doctor about her husband, she erroneously produced a picture of Jeff instead. (TV: The Wedding of River Song)