Karam was born in Taumarunui to a Lebanese father and Irish mother. He grew up on the family farm near Raurimu and attended St. Patrick's College, Silverstream.
A first XV player at Saint Patrick's, Karam scored 138 of the schools 239 points during the 1967 season. That year he was a North Island secondary schoolboys representative.
He spent the 1971 season with Horowhenua. He was selected for Wellington's South Island tour in 1972, becoming the youngest-ever player picked to represent Wellington. An extremely hard trainer at a club level, Karam was named as an All Black for the 1972–73 tour of the British Isles and France. He played 10 test matches for the All Blacks between 1972 and 1975.
Karam switched codes in 1975, signing a three-year deal with the Glenora Bears in the Auckland Rugby League competition $20,000 a year. Karam was horrified that players on the UK tour of 1971 got a pound a day as their living allowance while rugby officials "were flying around the world drinking champagne like it was going out of fashion". For players of "modest employment" slogging it out on the field for their country it meant that "their wife and children were starving back home".
He scored 160 points for the Bears in 1976, winning the Painter Rosebowl Trophy as top point scorer. He won the trophy again in 1977. Karam was selected for Auckland almost immediately, playing in six games in 1976 and scoring 53 points. This including playing in Auckland's 17–7 defeat of New South Wales City. He played in one game for Auckland in 1977, kicking six goals.
By the final year of his contract Karam couldn't break into the Glenora side, being succeeded by Warwick Freeman. He reportedly found the tackling work rate to be far more demanding than in rugby union.
Karam is known for his many years of unqualified support for David Bain, who was convicted in 1995 of murdering all five members of his family. Karam's research and sustained pressure on the justice system culminated in an appeal to the Privy Council in Britain in May 2007, at which Bain's conviction was overturned. The Privy Council found there had been a substantial miscarriage of justice, quashed his convictions and ordered a retrial. After his convictions were quashed, Karam allowed Bain to stay at his house in the Waikato on bail prior to the retrial two years later. Bain stayed for about three months before moving to Auckland. The new trial was held in 2009 and Bain was found not guilty on all five charges.
Without Karam's support it is unlikely there would ever have been a retrial. His interest in the case began in 1996 when he read a newspaper article about “an old music teacher and a bunch of young, long-haired university students” trying to raise money for Bain's appeal by selling jam. He went and gave them money. He began to study the evidence presented at the original trial and began to feel something was wrong with the case. He went to visit Bain in prison in Christchurch and subsequently visited him over 200 times. According to media commentator Paul Holmes, Karam was appalled at the way the family, the Police and the Fire Service arranged to burn the Bain house down.
Based on his extensive research over many years, Karam wrote four books about David Bain's case. The first was "David and Goliath: the Bain family murders" published in 1997. Karam made accusations against two individual police officers in David and Goliath as a result of which he was sued for defamation. (He won that case as well.) The book created a media furore. Karam appeared regularly on Holmes and 'did a thousand other media interviews'. The second book, "Bain and Beyond" was published in 2000 and the third, "Innocent!: seven critical flaws in the conviction of David Bain" came out in 2001. The fourth book "Trial By Ambush: The Prosecutions Of David Bain" was released in 2012. In this book, Karam accuses Robin Bain of the murders of his wife and three of their children before shooting himself.
Karam was paid $424,480 by Legal Services for his legal work in support of David Bain. Commissioner Nigel Fyfe approved the payment describing Karam's "unique circumstances" and said his legal assistance to Bain's defence was "exceptional" and the "equivalent to a non-qualified legal executive..."
While supporting Bain, Karam spent his 'considerable fortune' on the case. He'd become wealthy in various business ventures including hamburger bars and country pubs and the country's first major independent vending machine company. He had more than 20 investment properties, a launch and racehorses and lived on a 10-acre property in Clevedon. Karam says the crusade cost him millions and his friends estimated his personal losses could be as much as $4 million in terms of his time, loss of earnings and costs of legal and forensic experts. He spent it in his pursuit of the case and ended up living in 15 to 20 different rental houses over the past decade while trying to prove Bain's innocence. He received some compensation prior to the retrial by working as a researcher and investigator for Bain's legal team, where he was paid up to $95 an hour.
Karam acknowledges that fighting the case has taken its toll on him over the years. Interviewed in the New Zealand Herald in 2007 under the headline Joe Karam: Freedom Fighter, he said "For many years the mainstream media, judiciary and politicians just thought of me as a raving redneck who'd lost the plot." He stopped socialising with rich-list friends because people would inevitably "buttonhole him about the case" and he felt compelled to put them straight – "destroying the dinner party" in the process. He said that "every morning for two years, he would wake up, sink to the edge of the bed and cry". When asked what motivated him to keep going, he said it was because of his "innate hatred of unfairness and urge to help those less fortunate".
Karam has also taken legal action to defend himself in pursuit of the case. In addition to being sued for defamation by two police officers, he also took on the media with litigation against TVNZ, North and South magazine and the New Zealand Herald. He sued journalist Rosemary McLeod over an article that cast doubt on his motives for supporting Bain. They settled out of court. In 2011 he sued Trade Me for defamation over 349 posts on the website's public message boards about Bain.
In 2012 Mr Karam began legal proceedings against Kent Parker and Victor Purkiss for defamation. Parker and Purkiss were opposed to David Bain receiving compensation and made numerous derogatory comments about Karam on a number of websites. In April 2014, Justice Patricia Courtney identified about 50 defamatory statements published on Facebook and on a private website by Mr Parker and Mr Purkiss and awarded Karam $535,000. Kent Parker admitted the defamation under cross-examination and was ordered to pay $350,500. Vic Purkiss, who made defamatory posts on Facebook and Counterspin, was ordered to pay $184,500.
The judgement can be found here.
Karam was also awarded $64,774 in costs, and $11,350 disbursements. Journalist Jock Anderson said it was unlikely Mr Karam would ever receive any of the money because Mr Purkiss left the country and Mr Parker is bankrupt. Karam also sued Fairfax NZ because articles on stuff.co.nz drew attention to the websites that contained the defamatory comments by Mr Parker and Mr Purkiss but Fairfax settled out of court. Karam said the public campaign against his integrity had been the "worst four years" of his life.
Karam believes the fact that it took 13 years to get Bain's conviction overturned shows how flawed the New Zealand justice system is. In 2007 he said he planned to set up an organisation similar to the Innocence Project in the US, where those with skills and resources offer their help pro bono, like a support club for single crusaders such as himself, Keith Hunter and Mike Kalaugher (the Scott Watson campaigners).
An attempt to establish a New Zealand Innocence Project was made in 2009 by a group of lawyers concerned about the life sentence given to Alan Hall. In 2013, the project was re-launched out of the University of Otago, and has now been officially accepted as a branch of the Global Innocence network, becoming the world’s 63rd innocence project.
Following the Privy Council decision to overturn the murder convictions of Mark Lundy, Karam said the Lundy case shows again that "an independent body is needed to review potential miscarriages of justice". He says it is too hard for someone to fight their case from prison when the Governor General and the police effectively determine whether the original conviction is accurate. Mark Lundy was convicted at his retrial in 2015.Joe Karam: David and Goliath: the Bain family murders (Auckland: Reed, 1997) ISBN 0-7900-0564-6
Joe Karam: Bain and Beyond (Auckland: Reed, 2000) ISBN 0-7900-0747-9
Joe Karam: Innocent!: seven critical flaws in the wrongful conviction of David Bain (2001) (Auckland: Pohutakawa Productions, 2001) ISBN 0-473-07874-0
Joe Karam: Trial By Ambush: The Prosecutions Of David Bain (Harper Collins) ISBN 9781869508340