The feats of former Cabinet minister Hugh Templeton, mineralogist Emeritus Prof Douglas Coombs (who could not attend the ceremony), and the Very Rev John Murray were celebrated at a special ceremony at the school on Thursday.
Principal Dan Reddiex said the trio came from similar backgrounds to the school's present-day pupils, and showed what was possible with passion and determination to succeed.
Mr Reddiex said the trio brought the number of members on the wall of fame, which was established in 2010, to a dozen.
He said they exemplified this year's theme of "tall poppies" - standing out from the crowd, and from mediocrity.
Addressing the pupils, Mr Templeton urged them to use their school years to learn New Zealand history, especially the part played by strong characters such as Sir George Grey.
Even though pupils lived in a different world wrought by the technological revolution, the lessons of history remained essential, he said.
As former prime minister the late Sir Robert Muldoon's trade and industry minister, Mr Templeton was responsible for negotiating the closer economic relations trade agreement with Australia, Mr Reddiex said.
Mr Murray reflected on his political and social activism; as a "peacenik" he opposed nuclear war, armed conflict, and South African apartheid.
When he left the school in 1947 - a very different time from today - the post-World War 2 atmosphere was one of "guns, death, and the bomb", he said.
Pupils performed a haka as a finale to the ceremony.
