Briggs was known for his formidable punching power and aggression, possessing an 88.3% knockout-to-win rate with 37 knockout wins in the first round.

"[2] At age 17, Briggs began training at Jimmy O'Pharrow's Starrett City Boxing Club in Brooklyn, NY.

[8] Brigg's lawyer and adviser (equivalent of pro's manager) at that time was Mike Marley, the ex-Post boxing writer.

[citation needed] He suffered his first loss when he was knocked out in three rounds by undefeated Darroll Wilson in Atlantic City, New Jersey, in 1996.

[9] Briggs fought against lineal champion George Foreman on November 22, 1997, at the Trump Taj Majal Hotel & Casino in Atlantic City, New Jersey.

However, despite his record, his one loss had been a third-round knockout against Darroll "Doin' Damage" Wilson on HBO the previous year which halted his momentum and hurt his status as one of the premier up-and-coming heavyweights.

In the 12th and final round, Foreman tried hard for a knockout victory and was able to break Briggs' nose but was unable to score a knockdown.

After Briggs collapsed to the mat following a missed left hook, referee Frank Cappuccino stopped the fight and awarded Lewis the victory by technical knockout.

[19][20] Notable wins were against Ray Mercer, Brian Scott, Luciano Zolyone, Dicky Ryan and Chris Koval.

[21][22] Briggs won the WBO heavyweight title when he knocked out Sergei Liakhovich in the last round of a November 4, 2006, matchup.

The fight was rescheduled fifty days later in Atlantic City on June 2, 2007, with Briggs losing in a unanimous decision 117–111, 119–109, and 115–113.

He knocked out Rafael Pedro, Dominique Alexander and Rob Calloway all inside the first round of their respective fights.

On October 16, 2010, Briggs fought for the WBC heavyweight title against Vitali Klitschko in the O2 World at Hamburg, the fight billed as 'Thunderstorm'.

[31][32][33] In March 2016, Briggs confronted David Haye at his press conference for the announcement of his fight against little-known Arnold Gjergjaj at the O2 Arena on May 21, 2016.

[43][44] On November 22, VADA informed the WBC that Browne had failed a second drug test in the space of six months.

[45] On December 26, 2016 Alexander Ustinov's manager Vladimir Hryunov announced that he would be fighting for the WBA 'Regular' title on February 25, 2017, against either Briggs or Fres Oquendo.

[46][47] On January 4, 2017, the WBA ordered for a deal to be reached between Briggs and Oquendo within 30 days or they would force a purse bid.

[50] A bid of $400,000 was made by The Heavyweight Factory representative Henry Rivalta, on behalf of Briggs however not being valid due to not meeting the minimum requirement.

[51] On February 23, Square Ring Promotions and Hitz Entertainment Corporation announced that a deal had been reached for the Briggs vs. Oquendo fight.

CEO of Square Ring Promotions John Wirt told World Boxing News, “We are really excited that we were able to reach an agreement with Kris Lawrence and Henry Rivalta of The Heavyweight Factory.”[52] On March 16, Briggs announced via his Social Media accounts, the fight would take place June 3, 2017 at the Hard Rock Hollywood in Florida.

It was revealed that Briggs' collected sample had almost 8 times the regular amount of testosterone for a man of his age and weight.

[60] Briggs told Sky Sports that he would be applying for a British boxing license in order to fight in the UK.

He claimed he had licensing in the US and would likely appear on Tyson Fury's undercard on June 15 at the Thomas & Mack Center in Nevada.

[63] After a back and forth over some years,[64] Briggs and former Ultimate Fighting Championship light heavyweight champion Quinton "Rampage" Jackson were aiming to have an exhibition boxing match in 2024.

He made his television acting debut on New York Undercover in 1995 and has since appeared in feature films Bad Boys II, with Will Smith and Martin Lawrence, Transporter 2, and The Wackness.

He appears in the music video for rapper Thirstin Howl III's song "Surrounded By Criminals" (from his 2011 album Natural Born Skiller).

Applied BioSciences, a cannabinoid therapeutics company, focused on medical, bioceutical, testing and pet health industries.

Briggs stated, “I have partnered with Applied BioSciences to develop and market Champ Organics because their products are made with the highest quality ingredients and all-natural CBD.

Briggs became a well known figure in the influencer boxing scene, with his catchphrase "let's go champ" being the subject of several viral memes.