His wife, Catherine Milnes-King, said the depth of her grief in losing her soul-mate was like a black hole.
About 800 mourners packed out the Wellington Cathedral of St Paul today to farewell the 43-year-old, who died suddenly next to his car in suburban Newlands a week ago.
In an emotional tribute to her husband of 15 years, Ms Milnes-King said he was gentle, loving, affectionate.
"He felt enormous empathy at human suffering and he carried the responsibility of others' burdens."
Among those at the service were members of the legal community, police, journalists, emergency workers and gang members.
National MP Tony Ryall, who has been a friend of Mr King's for 13 years, said his death was a great loss to New Zealand.
"He was more than just a brilliant lawyer, more than this thoughtful and driven man. He was a sports fan and art collector, a wine connoisseur, a fellow admirer of shirts that made a statement and he had a great sense of timing and humour."
Mr King's legal achievements were lauded.
He was recognised as New Zealand lawyer of the year in 2007 and a few months ago he took up the Eisenhower Fellowship and was writing essays comparing the New Zealand and United States legal systems.
His plain pine coffin was draped with his court robe, wig and trusted initialled blue bag that always held his robe.
Justice William Young said Mr King was known for the empathy he felt for victims of crime.
Crown prosecutor Simon Moore said Mr King was "scrupulously honest".
"If Greg said it was so, it was, because his word was his bond."
It was a tribute to Mr King that people representing all aspects of the legal profession as well as victims of crime felt a keen loss at his death.
Robert Lithgow, QC, said Mr King was admired among the legal fraternity because he was the type of lawyer who always made an effort and added value to the predicament people got themselves into.
"He was one of those lawyers who could find something good even in the most unsatisfactory of people."
Judith Ablett-Kerr had hired Mr King when he was starting out in the profession.
She said his talent knew no boundaries and his energy was boundless.
Mr King's father, Jeffrey King, said he and his wife were the most fortunate people in the room because they had known their son for 43 years.
His son hadn't left them - he could see Greg King in his two young daughters.
"In the eyes of Pippa and Millie's just a character."