He previously played for the New Zealand Warriors and Penrith Panthers. He primarily plays as a second-rower, but can also fill in at centre and hooker. Brown started his rugby league career playing for the Riccarton Knights in Christchurch and attending Papanui High School.
He played junior representative football for Canterbury and was a New Zealand under-16 representative.
He debuted for the Canterbury Bulls in the 2005 Bartercard Cup. Brown is related to former New Zealand representative Brendon Tuuta.
Brown moved to Sydney, playing for Cronulla"s feeder side Griffith. There he was spotted by scouts from the Sydney Roosters and they signed him for their Jersey Flegg Cup side.
He later moved to join Balmain-Ryde and the Wests Tigers, playing for their New South Wales Cup side.
While he was a feature in the Premier League side he could not break into the first grade side due to the presence of Robbie Farah and John Morris. In 2008 the Warriors announced that they had secured Brown for the 2009 season on a one-year deal, with an option for another year. He joined the Warriors in October 2008 but arrived with a major foot injury, which hampered his pre-season.
He made his National Rugby League debut for the Warriors on 3 May 2009, playing against the Street George Illawarra Dragons.
In 2010 he signed an extended contract that kept him at the Warriors until 2012. On the 28 March 2012, Brown signed a 3-year contract with the Penrith Panthers, commencing in the 2013 NRL season.
On 20 June 2015, Brown signed a 3-year contract with the Manly Warringah Sea Eagles starting in 2016. Brown was named in the New Zealand Kiwis squad for the 2010 Four Nations and played for the New Zealand Māori against England in the build up to the tournament.
Lewis Brown made his international debut for the New Zealand Kiwis in the 2011 ANZAC Test against Australia.
He was originally named on an extended bench, and made his debut after when Greg Eastwood withdrawn through injury. He also set up Kiwis" debutant winger Matt Duffie for a try in the 36th minute of the game. Made a tremendous impact within minutes of taking the field during the first half of the Australia V. New Zealand Four Nations game, scoring an impressive try as a result of a Greg Inglis knock on.