In the mid-1990s, Lamo volunteered for the gay and lesbian media firm PlanetOut Inc. In 1998, Lamo was appointed to the Lesbian, Gay, Bisexual, Transgender, Queer and Questioning Youth Task Force by the San Francisco Board of Supervisors.

In December 2001, Lamo was praised by Worldcom for helping to fortify their corporate security. In February 2002, he broke into the internal computer network of The New York Times, added his name to the internal database of expert sources, and used the paper’s LexisNexis account to conduct research on high-profile subjects. The New York Times filed a complaint, and a warrant for Lamo’s arrest was issued in August 2003 following a 15-month investigation by federal prosecutors in New York. At 10:15 a.m. on September 9, after spending a few days in hiding, he surrendered to the US Marshals in Sacramento, California. He re-surrendered to the FBI in New York City on September 11, and pleaded guilty to one felony count of computer crimes against Microsoft, LexisNexis, and The New York Times on January 8, 2004.

Lamo used a wide variety of supplements and drugs throughout his life. His wife, Lauren Fisher, called his drug use “body hacking”. One of Lamo’s preferred supplements was kratom, which he used as a less-dangerous alternative to opioids. In 2001, he overdosed on prescription amphetamines. After he turned in Manning, his drug use escalated, but later claimed that he was in recovery.

On August 22, 2002, Lamo was removed from a segment of NBC Nightly News when, after being asked to demonstrate his skills for the camera, he gained access to NBC’s internal network. NBC was concerned that they broke the law by taping Lamo while he (possibly) broke the law. Lamo was a guest on The Screen Savers five times beginning in 2002.

Hackers Wanted, a documentary film focusing on Lamo’s life as a hacker, was produced by Trigger Street Productions, and narrated by Kevin Spacey. Focusing on the 2003 hacking scene, the film features interviews with Kevin Rose and Steve Wozniak. The film has not been conventionally released. In May 2009, a video purporting to be a trailer for Hackers Wanted was allegedly leaked to or by the Internet film site Eye Crave. In May 2010, an earlier cut of the film was leaked via BitTorrent. According to an insider, what was leaked on the Internet was a very different film from the newer version, which includes additional footage. On June 12, 2010, a director’s cut version of the film was also leaked onto torrent sites.

In July 2004, Lamo was sentenced to two years’ probation, with six months to be served in home detention, and ordered to pay $65,000 in restitution. He was convicted of compromising security at The New York Times, Microsoft, Yahoo!, and WorldCom.

In a 2004 interview with Wired, an ex-girlfriend of Lamo’s described him as “very controlling”, alleging “he carried a stun gun, which he used on me”. The same article claimed a court had issued a restraining order against Lamo; he disputed the claim, writing: “I have never been subject to a restraining order in my life”.

On May 9, 2006, while 18 months into a two-year probation sentence, Lamo refused to give the United States government a blood sample, which they had demanded to record his DNA in their CODIS system. According to his attorney at the time Lamo had a religious objection to giving blood but was willing to give his DNA in another form. On June 15, 2007, lawyers for Lamo filed a motion citing the Book of Genesis as one basis for Lamo’s religious opposition to the giving of blood.

On June 20, 2007, Lamo’s legal counsel reached a settlement agreement with the U.S. Department of Justice whereby Lamo would submit a cheek swab in place of the blood sample.

In February 2009, a partial list of the anonymous donors to the WikiLeaks not-for-profit website was leaked and published on the WikiLeaks website. Some media sources indicated at the time that Lamo was among the donors on the list. Lamo commented on his Twitter page, “Thanks WikiLeaks, for leaking your donor list … That’s dedication.”

In May 2010, Lamo reported to U.S. Army authorities that then Bradley Manning had claimed to have leaked a large body of classified documents, including 260,000 classified United States diplomatic cables. Lamo stated that Manning also “took credit for leaking” the video footage of the July 12, 2007, Baghdad airstrike, which has since come to be known as the “Collateral Murder” video.

Lamo was criticized by fellow hackers, such as those at the Hackers on Planet Earth conference in 2010, who labeled him a “snitch”. Another commented to Lamo, following his speech during a panel discussion, saying: “From my perspective, I see what you have done as treason.”

Lamo said in a Wired article that, in May 2010, after he reported the theft of his backpack, an investigating officer noted unusual behavior and placed him under a 72-hour involuntary psychiatric hold, which was extended to a nine-day hold. Lamo said he was diagnosed with Asperger syndrome at the psychiatric ward.

In April 2011, WikiLeaks founder Julian Assange called Lamo “a very disreputable character”, and said it was not right to call him a financial contributor to WikiLeaks, since Lamo’s monetary support amounted to only US$20 on one occasion. Assange said it was “mischievous to suggest the individual has anything to do with WikiLeaks.”

On July 13, 2011, Wired published the Lamo–Manning chat logs in full, stating: “The most significant of the unpublished details have now been publicly established with sufficient authority that we no longer believe any purpose is served by withholding the logs.” Greenwald wrote of the newly released logs that in his opinion they validated his claim that Wired had concealed important evidence.

For a period of time in March 2011, Lamo was allegedly “in hiding”, claiming that his “life was under threat” after turning in Manning.

Lamo also appeared on Good Morning America, Fox News, Democracy Now!, Frontline, and repeatedly on KCRA-TV News as an expert on netcentric crime and incidents. He was interviewed for the documentaries We Steal Secrets: The Story of WikiLeaks and True Stories: WikiLeaks – Secrets and Lies. Lamo reconnected with Leo Laporte in 2015 as a result of a Quora article on the “dark web” for an episode of The New Screen Savers.

Lamo died on March 14, 2018, in Wichita, Kansas, at the age of 37. Nearly three months later, the Sedgwick County Regional Forensic Science Center reported that “Despite a complete autopsy and supplemental testing, no definitive cause of death was identified.” However, many bottles of pills were found in his home. Several of the pills found there were known to cause severe health problems when combined with kratom. As a result, evidence points to an accidental death due to drug abuse.