Graham received the membership at a special meeting of the union last night.
Graham made his debut for Otago aged 18 in 1975, having moved south from Tauranga.
He went on to play more than 100 games for the union, captained the team and also played eight matches for the All Blacks, including one test.
A loose forward-lock, Graham (63) played for the University, Dunedin and Clinton clubs.
He also coached club teams Dunedin and Zingari-Richmond.
He coached Otago in 2001-05 and was on the board in 2009-13.
He was chairman of the board when the union got into financial trouble in 2012 and helped it narrowly avoid going out of business.
He left the board a year later.
Graham said last night it was humbling and a huge honour to receive the life membership.
