Before he was turned into a vampire by Bishop, Tommy had a wife and child. It was Bishop's promises of building a new world that enticed Tommy to embrace unlife and leave his family behind.
After Aidan killed Bishop, Tommy and about a dozen other newborn vampires became "orphaned". At first he tries to obey Aidan's command to not feed on humans, but this proves to be almost impossible for Tommy, who lacks Aidan's willpower. Aidan starts feeding him and the other orphans hospital blood to sate their hunger, with little effect.
Later, he finds out that Mother has ordered the mass execution of the orphaned vampires. He begs Aidan to help save him, but Aidan could only urge him to flee Boston and live under the rader to escape Mother's wrath. Tommy ignores this advice, and he and two other orphaned vampires decide to try and assassinate Mother instead, Aidan defends Mother and stakes Tommy in a haze of adrenaline, who has a look of betrayal on his face as he crumbles to ash.