The 65-year-old Mosgiel real estate agent has a new lease on life after recovering from a rare terminal lung disease, idiopathic pulmonary fibrosis.
Without the transplant, he would have died.
''I struggle to find a word that I can use to explain my feelings ...
''All I know is that I'm humbled by it - the fact that somebody as a donor and the family of a donor made that decision to allow transplants.''
He spent three months in Auckland at the start of this year - two of them in Auckland City Hospital - for the lung transplant, his hospital stay longer than expected because he went into septic shock 10 days after the surgery.
He has been back at work since about July, after more than a year off.
Getting him back to good health was a team effort, from hospital specialists to the cleaners and porters; from the donor and their family to his own family and the Mosgiel community.
''Everybody that was involved ... they were all part of what I call the jigsaw of my life at the time, whether they be a big jigsaw part or a small jigsaw part, and they should all be congratulated.''
By the time he had his operation in January, he had severely restricted mobility and had organised his funeral. He was given the lungs of a 50-year-old, and said he wanted this story to be about the vital role of donors rather than ''my dramatics''.
Mr McLachlan is offering his time to service groups and other organisations to talk about the role of donors and transplants.
His was the 165th lung transplant performed in New Zealand.
He thanked his wife, Helen, and his three children for their support.