The 45-year-old winner of Celebrity Big Brother 2010 was sentenced to eight weeks in prison after being convicted of contempt of court for giving a false statement in his insurance claim.
Reid attempted to claim compensation after his Audi A6 was involved in a car crash with a Seat Leon on the A41 in north London in 2018.
Watch: Katie Price confirms she is engaged to Carl Woods!
The former cage fighter said a stranger on a motorbike had volunteered himself as a witness before police arrived on the scene.
But the witness turned out to be kickboxing champion Darren Summers, who trained Reid for his first cage fight.
Axa insurance, who represented the other driver, brought the case to the High Court for a committal hearing where Reid was convicted. He has been sentenced to eight weeks behind bars but will be released on licence after four.
Justice Eady said he made “a deliberate falsehood in which the defendant stood to make significant financial gain.”
She also rejected claims he should be treated different because of his “celebrity".
Reid began dating reality star Katie Price in 2009 and they married in Las Vegas in 2010, only to split less than a year later in January 2011.
He went on to date fellow Celebrity Big Brother winner Chantelle Houghton. The couple – who split in 2012 – share an eight-year-old daughter, Dolly.
Reid is currently expecting a baby girl with fiancee Nikki Manashe. The couple revealed in November last year that Manashe was four weeks pregnant with twins after a seven-year IVF battle. She tragically miscarried one of the babies in December.
She was previously engaged to Warren Furman, aka Ace from Gladiators, in the late 90s before going on to marry Peter Andre in 2005).
After Price split from Reid she was briefly engaged to Leandro Penna in 2012 before marrying Kieran Hayler in 2013. She had another fleeting engagement to Kris Boyson in 2019, before meeting Woods at the beginning of 2020.
Watch: Alex Reid dressed up as a cow