The Associated Press called him "a gifted writer in the tradition of William Burroughs and Hunter S. Thompson" who had "a knack for self-sabotage and has struggled with heroin addiction and depression.

[8] Brown exhibited an early interest in writing and journalism, creating his own newspapers on his family's computer while attending Preston Hollow Elementary School where he was the poet laureate.

"[17] In 2000 he enrolled at the University of Texas at Austin and spent two semesters taking writing courses before leaving school to pursue a full-time career as a freelance writer.

[18] In 2010, Brown began work on his crowdsourced investigation wiki, Project PM, which was labeled a "criminal organization" by the Department of Justice.

[21] The group dug through huge amounts of hacked files and emails from intelligence contractors, hoping to expose companies like HBGary and Stratfor,[21] earning the trust of the hacktivist community.

[4] According to outlets like The New York Times and Rolling Stone, Brown called his research subjects at home and harassed them, which some Project PM members considered pranks and joined.

[14][18][22][23] In June 2011, he and Project PM released an exclusive report about a surveillance contract called "Romas/COIN" which was discovered in e-mails hacked from HBGary by Anonymous.

[7] In 2016, after Brown was released from prison, he posted crude videos and conspiracy theories online and was accused of harassing women, which he denied.

[11][12][23] In 2017, Brown launched the Pursuance Project, which aimed to unite transparency activists, investigative journalists, FOIA specialists and hacktivists in a fully encrypted platform.

[21] Brown said that Pursuance would take hacktivism into the future, letting anyone sort through troves of hacked documents and even recruit teams of hackers.

He also discussed starting abusing methamphetamines a year and a half earlier, noting it elevated his work and his ability to wreak havoc on elements of the press and police agencies.

"[23]Brown began working with Anonymous after watching it form in 2006 and being asked "to help run things in a way and to participate" and become directly involved when Operation Tunisia started in January 2011.

[14][36] He called himself a "senior strategist" and "propagandist" for the group, describing his work as "information operations" and "sort of an unconventional, asymmetrical act of warfare".

[58] On November 5, Forbes reported that Brown alleged that emails showed that district attorney Ron Moore in Asheville, North Carolina had been cooperating with drug cartels.

[57][61] Brown commented that "I don't know for a fact that Ron Moore is involved with these gangs, but I have information that I’ve provided to others that makes it look like that.

[62] In his memoir, Brown wrote OpCartel "fizzled out" after he "made a few halfhearted efforts to obtain information" but that he "lacked the wherewithal to get anything accomplished" and was working through "a haze of opiates and mania" during the events.

Barrett Brown, a long-time defender of WikiLeaks, was exasperated that Assange was "complaining about 'slander' of being pro-Trump IN THE ACTUAL COURSE OF COLLABORATING WITH TRUMP".

"[65] Brown said Assange had acted "as a covert political operative", thus betraying WikiLeaks' focus on exposing "corporate and government wrongdoing".

In the United States, he agreed to a plea bargain in 2014 and plead guilty to accessory after the fact in the unauthorized access to a protected computer, threatening an FBI agent and obstructing the execution of a search warrant.

Journalists familiar with the evidence against Brown said the total number of pages of chat logs may have been in the tens of thousands, potentially revealing his contacts with hackers and other sources who thought they were speaking in confidence.

[34] Brown has talked publicly about his history of using heroin[40][16][22] and said at his sentencing that he was going through "sudden withdrawal from paxil and suboxone" on the day he made the video.

[79][80] A trove of millions of Stratfor emails from the hack, including authentication information for thousands of credit card, was shared by the hacker collective LulzSec with WikiLeaks.

[81] On January 23, 2013, a third indictment was filed against Brown on two counts of obstruction for concealing evidence during the March 6, 2012, FBI raid of his and his mother's homes.

[89] In April 2014, Brown agreed to a plea bargain and plead guilty to accessory after the fact in the unauthorized access to a protected computer, threatening an FBI agent and obstructing the execution of a search warrant.

D Magazine wrote that the logs "painted Barrett as a leader of Anonymous, someone who knowingly stole and distributed credit card information, a wreaker of real and serious damage" in an attempt to secure a lengthy prison sentence.

According to Brown, instead of using that information "they subpoenaed a media organization that they happen to have a great deal of interest in, The Intercept" which he called "an ill-thought-out fishing expedition".

[7][108] In May 2021, he was arrested on Sylvia Mann's canal boat in east London, being there since November 2020 to claim asylum, for overstaying his visa[8] and two incitement offenses related to the banner.

An internal memo included a statement by Metropolitan Police Federation Chair Ken Marsh calling the banner "abhorrent, unacceptable, and dangerous behaviour" that could have resulted "in a tragedy."

The fourth and final ban was prompted by Brown tweeting that Assange should not be on trial but that he would "deserve to die by other, cleaner hands" if he knew of Erik Prince's alleged ties to Roger Stone.

[125][131] On July 9, 2024, the day his book My Glorious Defeats: Hacktivist, Narcissist, Anonymous was published, Brown announced that he was sober again and going to start a twelve-step program.