"Sir Peter has assisted various league communities around the country raise funds for local needs," said NZRL chief executive Alex Hayton.
"No-one knows how much money he has raised or assisted the game with.
"He has been a confidante to various NZRL CEO's and boards, providing a respected independent voice. He has singlehandedly raised the sport's profile in New Zealand, and is internationally respected by the Australian Rugby League and the Rugby Football League.
"Sir Peter's contributions are outside the normal life membership criteria, but his exception service to the game deserves the ultimate recognition by the game."
The colourful Leitch was near speechless in accepting the honour.
"I'm very humbled to be here today," he said.
"I don't do what I do to get awards - it's all about the fellowship and you can't buy that.
"To join the elite of the life members is a great honour and I thank you."
Former NZRL chief executive Mike Knowles reflected on a time when Sir Peter's Mad Butcher outlets were also used as a ticket agency for major rugby league fixtures.
"People would arrive a the Carlaw Park turnstiles with tickets covered in blood, because the person who sold them had just finished cutting up meat."
NZRL now has 16 life members and while Leitch's inclusion was announced today, he will officially receive the honour at a special presentation ceremony later this year.
Meanwhile, the annual meeting elected former director Bill McEntee back onto the NZRL board, replacing long-serving Ray Haffenden, who had been on the board since 2006.