Nicholas (Nic) Davidson QC, 76, acted for some of them on a pro bono basis.
He represented the Serious Fraud Office into the Wine Box Inquiry, and was counsel for the Pike families in 2010.
He often worked out of Hannan and Seddon offices in Greymouth at that time.
In 2015 Mr Davidson was appointed as a judge to the High Court.
He said at the time his involvement in the Pike River inquiry had been a life-changing experience.
The Royal Commission had involved "magnificent, resolute families".
"It was an immersion in a story which many, with reason, were reluctant to tell."
He retired in December 2018.
Pike River widow Anna Osborne said today Mr Davidson had done "a lot" of pro bono work.
"Some of those men you expect to live forever ... when I heard the news I was really shocked. He had such a kind heart."
He was not pompous and would sometimes have the grandchildren in his car when she called, and would pull over for a chat.
During morning tea, lunch, and afternoon tea at the inquiry, he would talk the families through what had been said, in plain English.
Speaking after charges were initially dropped over a decade ago, Mr Davidson said it was appalling that no one had been found responsible.
Police are still to make a decision on whether to lay new charges.
Mr Davidson was also part of the ethics committee of global football governing body, Fifa, one of just six investigatory chamber members worldwide.
He quit the position in 2015, reportedly frustrated by the limitations placed on the independent panel by Fifa during corruption enquiries.
He died on Saturday and a memorial service will be held at a later date.
