The Dunedin man received the rare honour of a Red Cross honorary life membership last week, in appreciation of his decades of service over 67 missions for the humanitarian organisation.
Mr Clark (74) remains an on-call disaster response delegate, but he said he now serves in more of an advisory role. He described his work as several jobs rolled into one: accountant, logistician, team-leader and procurement specialist.
When the Red Cross got word of a disaster, it was up to Mr Clark to assist with wrangling the equipment, staff and funding required to deal with the aftermath. He would then travel to the affected area as one of the first on the front-lines to help with the clean-up.
One disaster looms large in his memories of the job: the Indian Ocean earthquake and tsunami on Boxing Day 2004.
"That was my big one."
Mr Clark remembered finding a finely-cut rose on the ground in the southern city of Galle, one of the worst hit areas in the tsunami, and asking his guide where it had come from.
"He said `there had been a wedding here'.
"This wedding party was completely wiped out."
He still had the rose.
Red Cross national and international disaster management officer Andrew McKie, Mr Clark's longtime boss and friend, paid tribute to his years of service, and his willingness to drop everything at a moment's notice.
"He always had a bag packed."