Lieutenant Foster was an operations division United Earth Starfleet officer who served on board Enterprise during the 2150s, under Captain Jonathan Archer.
In 2153, Foster served as a security guard for the two assimilated Tarkaleans in sickbay. He was thrown against a wall when he tried to stop them, when they successfully attempted to escape sickbay.
He later assisted Doctor Phlox with his omicron radiation treatment. (ENT: "Regeneration")