Although Brendon has continued to work as an actor, with regular recurring parts in TV series and starring roles in limited release films such as Coherence and Big Gay Love, his struggles with substance misuse and depression have overshadowed his professional career.

[5] Instead, he decided to pursue acting to help manage his stutter,[6] which had first become apparent at age seven or eight, and had made him so fearful of speaking or interacting with strangers that he did not begin dating until 21 or 22.

He was involved with the show's canonical comic book series, Buffy the Vampire Slayer Season Ten, on stories centering on his character.

That same year, he reunited with his former Buffy the Vampire Slayer co-star Charisma Carpenter in the ABC Family TV movie Relative Chaos.

From July 26 through August 30, 2006, Brendon co-starred with Noah Wyle in the play Lobster Alice at the Blank Theatre Company in Los Angeles.

He subsequently appeared in the Blank Theatre's annual Young Playwrights Festival[16] and its productions of The SantaLand Diaries (November 20 to December 20, 2009),[17] and Why Torture Is Wrong, and the People Who Love Them.

[18] In 2007, Brendon began appearing on the TV series Criminal Minds in the recurring role of FBI technical analyst Kevin Lynch.

The comic follows the journey of two sheltered and innocent koalas experiencing a variety of people and places while on the run from the law in a 1958 Cadillac El Dorado.

[22] Also in 2010, Brendon began a four-episode arc on ABC's Private Practice playing Lee McHenry, a mentally disturbed man who assaults Charlotte King.

Brendon has struggled for many years with depression and alcoholism, leading to many run-ins with the law and multiple arrests and several convictions for destruction of property, vandalism, theft and domestic violence.

[30] Brendon pleaded no contest to all four charges in June 2010 and received a one-year suspended jail sentence, was placed on probation for 36 months, and was required to perform 10 days of community service.

[31] While participating in the Tree City Comic Con, Brendon was arrested on October 17, 2014, in a Boise, Idaho, hotel lobby for misdemeanor charges of malicious injury to property and resisting or obstructing officers.

Brendon subsequently made a public apology and stated that the incident was "embarrassing" and the result of drinking alcohol while taking pain medication for a knee problem.

Brendon was arrested on suspicion of grand theft by Fort Lauderdale police in February 2015 after he reportedly trashed his hotel room and refused to pay the bill.

Brendon later explained on his Facebook page that he had been drinking before the interview and had felt unprepared to "lay [out] the darkest parts of myself on national TV".

[36] Brendon returned to Dr. Phil in December that year to discuss his arrests and mental health struggles, including several suicide attempts.

As part of his plea deal, Brendon avoided a custodial sentence if he completed drug and alcohol counselling and one year of probation.

[44] Brendon subsequently agreed to a plea deal to avoid a potential four-year prison sentence for felony domestic violence, and violation of active protective orders issued by two states.