He is survived by his wife, Catherine Milnes-King, and daughters Pippa, 5, and Millie, 3.
His death is not considered suspicious and has been referred to the coroner.
Mrs Webb, who lives in Blenheim, said although Mr King was not the leader of the pack or opinionated at school, he was not shy either, and did everything to the best of his ability.
"He was a great guy at school. He was always in the debating team and that sort of stuff. You always knew that he was going to make something of himself.
"The fact that he became a great criminal lawyer didn't sur prise me at all.''
She said Mr King had been a very good head boy at the school and after he left school, attended Expo 88 in Brisbane before heading to university.
Fellow classmate Mel Hoverd said she also remembered Mr King as quiet and that he was "a very bright cookie''.
"There were only three of us in the whole school that passed all of our School Certificate subjects and Greg was one of them.''
Sheree Winter, who attended Tongariro High School several years ahead of Mr King and whose children also went to the school, said Mr King was the speaker at the school's prizegiving several years ago and was always proud of
the fact he had grown up in Turangi.
"I think the point he was trying to drive home was that it didn't matter where you went to school, it was entirely up to you what you made of it.''
Law Society president Jonathan Temm, from Rotorua, said lawyers faced enormous pressure and that Mr King had been affected by public condemnation of the not guilty verdicts against Macdonald.
Mr Temm said the case took its toll in the form of public condemnation of Mr King.
"When you pick up a newspaper or turn on a radio and people are slagging off the outcome, that indirectly reflects on him too,'' Mr Temm said.
Mr King was a ``brilliant lawyer'' who accepted unpopular cases, which took courage.
In 2009 he was on the defence team for Clayton Weatherston, who murdered his ex-girlfriend Sophie Elliott; in 2008 he represented Daniel Moore, who was convicted at trial of the murder of Tony Stanlake; and Mr King also
represented John Barlow who was convicted for the murders of Wellington businessmen Gene Thomas and his son Eugene Thomas.
``He represented them with brilliance and determination. Greg had a rare skill. He was an orator from a kind of bygone age,'' Mr Temm said.
Mr King was born in Wanganui and raised in Turangi.
Family spokeswoman Frances Jones asked for the family's privacy to be respected as they came to terms with the news.
``This is a terrible tragedy for Greg's family and children, who are devastated by his loss.''