Mr Rush joined artist Barry Cleavin in a ceremony in front of the entire school yesterday to receive their honour. The late businessman James Valentine was the other recipient.
Rush attended King's High School from 1977 to 1980 and is considered one of the great marathon swimmers, setting many long distance swimming records in his 10-year career.
His most notable record was in 1987 when he crossed the English Channel three times in a row - 140km in 28 hours and 21 minutes.
Rush was inducted into the New Zealand Sports Hall of Fame in 1996.
King's High rector Dan Reddiex described Rush as a man with incredible determination and fortitude, saying that his ''tough mental approach'' was a key factor in his success.
Mr Rush said it was a great honour to receive the induction. He had key messages for the ''attentive and interested'' pupils.
''Make the most of your opportunities. Even if you don't succeed, you've given it a go. And that's what I want to get across.
''And don't take up marathon swimming. It's bloody boring,'' Mr Rush said.
Barry Cleavin attended King's High from 1953 to 1958 and explored printmaking for 50 years.
In 1983, Cleavin was awarded a Fulbright scholarship and in 2001 he was honoured as an Officer of the NZ Order of Merit for his services to the arts.
Born and raised in Dunedin, Cleavin then spent 50 years in Christchurch before the earthquakes damaged his home. But he had returned home after purchasing a house earlier this year ''down the bay''.
Cleavin said he was at his greatest peace when at his desk working on his art and that he was truly appreciative yesterday to receive his award.
''I was at peace in the hall there as well. And it was a wonderful feeling,'' he said.
James Valentine left King's High in 1938 after three years as a prefect and dux. He enlisted in the air force for World War 2 and spent three years as a prisoner of war in Java.
When he returned, he resumed his bachelor of commerce studies part-time and graduated with the highest marks in New Zealand for accounting in 1947. He was elected a life member of the NZ Society of Accountants in 1980.
Mr Reddiex said few New Zealanders could look back on such a comprehensive association with business and education.
