Matthew Brennan, born and currently known as Max Keenan, is Joy Keenan/Temperance Brennan's and Kyle Keenan/Russ Brennan's father. He and his late wife Ruth Keenan/Christine Brennan, disappeared when Temperance and Russ were teenagers, after going out to "run errands". It is revealed that they were career criminals who went into hiding after committing many crimes as fugitives. Though his wife died from skull trauma in 1993, Matthew continued living in hiding for years, until Russ' life was threatened. Max killed the Deputy Director of the FBI, who had been planning to kill Russ. Max gave Temperance a tape from her mother that was supposed to be for her sixteenth birthday, and, on a separate occasion, a ring from her grandmother.
Despite his malicious past he is a very kind, charming man who is very loving and affectionate with his daughter. It has been stated that his main problem is that his attitude consists of a moral framework that allows him to commit any action, including murder, so long as it is done for what he perceives as the right reasons; Special Agent Seeley Booth himself has noted that Max has never killed anyone who did not definitively deserve to die.
When he was finally brought to trial for the murder of Deputy FBI Director Robert Kirby ("The Verdict in the Story"), Max was cleared of the charges, but only on a technicality; after forensic evidence determined that Kirby had actually been killed by a small ornamental dagger in Brennan's apartment rather than Matthew's trademark copper pipe, the defense counsel pointed out that it was equally plausible for Temperance or Russ Brennan to have killed Kirby, prompting the charges to be dismissed due to there being no evidence to specifically incriminate any potential suspect (Although Booth himself risked jeopardizing that defense by stating that Brennan could not commit murder).
In The Bone that Blew, Max got a job at the Jeffersonian as a science teacher, a job he had before he went into hiding.
In Season 5, Matthew revealed to Temperance that he is friends with her cousins online, when convincing her to have a family Christmas.
- Presumedly committed numerous crimes prior to the start of the series
- Committed an unknown robbery for which he was sent to Cook County Jail in 1966
- Robbed a Piggly Wiggly in Carbondale, Illinois in 1978
- Robbed Ohio First Savings and Loan in 1978 (three fatalities; committed with a gang):
- Two innocent bystanders
- One state trooper
- Seven bystanders (injured only)
- Garrett Delaney (shot in the head with a .22 handgun, gutted and set on fire)
- Robert Kirby (stabbed in the back of the head with a misericorde, gutted and set on fire)
- Veleska Miller (tortured for information on Booth)
- Heather Taffet (attempted to kill her)
- Christopher Pelant (attempted to kill him)
Victims by ProxyEdit
- Vince McVicar (ordered Mitchell Downs to shank him in prison)
- No mention of his murder of Garrett Delaney was mentioned after Judas on a Pole, even during his trial in The Verdict in the Story, suggesting that Kirby's murder was the only murder they could forensically connect to him.
- ↑ In a later episode, Booth states that Max never killed any civilians or honest cops, suggesting that Max wasn't responsible for the fatalities of the robbery