Tom is tall and slim, with graying brown hair and crinkly blue eyes. He wears wire-rimmed glasses.
Tom and his ex-wife Ashley divorced when Hanna was in seventh grade. He soon began to date a nurse from Annapolis named Isabel. She has one daughter named Kate, who has always made Hanna feel insecure. Tom and Hanna barely interact in the years after he leaves their home. His seemingly perfect life with his new partner and stepdaughter makes Hanna very bitter. When he invites his daughter and "Alison" to meet Kate and Isabel, he obliviously pokes fun at Hanna's weight, resulting in the start of her bulimia. When Tom sees his daughter for the first time in four years, he is shocked by the changes in her. He has returned to Rosewood after getting the news that she crashed her ex-boyfriend's BMW and arranges to have her volunteer at Dr. Ackard's burn clinic. Tom tries to make amends for being absent for the past several years and invites Hanna to Le Bec Fin, an exclusive French restaurant in Philadelphia. However, he is disappointed when she complains about the presence of Isabel and Kate. He is even more upset when he finds out that Hanna sneaked off to the Foxy dance and has packets of Percocet pills.
Tom doesn't speak to his daughter again until moving back into the Marin home. Ashley has taken a job in Singapore and needs someone to look after Hanna. He, Isabel, and Kate move in and he sternly tells Hanna that she must start getting along with her stepsister. Tom makes Hanna help Kate through her first few days at Rosewood Day High. He is infuriated when Kate tells him about a nasty rumor Hanna spread at the Hastings fundraiser about her having herpes. Disappointed in his daughter's behavior, Tom tells her that she will start spending all of her free time with Kate. In "Heartless", Tom decides to send Hanna to the Preserve at Addison-Stevens, a luxury clinic for troubled patients. Convinced that her erratic behavior can be solved, he takes a reluctant Hanna to the Delaware institute. After Ashley finds out about Tom's actions, she kicks him and his family out of the house and returns to Rosewood. Throughout the series, it is painfully obvious that Tom doesn't know or understand his daughter anymore.
He is currently running a campaign in hopes of being elected as a US Senator. His specific politics, however, are unknown, other than the fact that his platform includes abolition of underage drinking. It is even unclear whether he is running on a democrat or republican platform. After Hanna steals $10 grand from her father's campaign money (which was hidden in a safe that Hanna cracked using Kate's birthday digits), he questions her. She denies her actions and convinces him to fire his campaign manager Jeremiah, who sniffs at Hanna being included in her father's promotion anyway. At first, Tom was going to exclude Hanna from his promotional commercial altogether, but when he sees how badly this offends her, he takes back his offer, and she is prominently included. In fact, the campaign staff think Hanna is relatable and an asset to her father's image, bringing the estranged father and daughter a bit closer for once.
In Deadly, they're estranged once agin after it becomes painfully obvious that he cares more about the campaign than he ever will for her. Hanna is taken off as an asset for it and is disowned for the "embarrassment" she has caused him. Mike tells a crying Hanna she doesn't own him which she reluctantly agrees to. This damages their relationship to the point of no return.