He served in the Royal New Zealand Navy for eleven years, including service on a frigate in the Korean War.

As a result of the pulmonary edema Mulgrew suffered frostbite to both his feet which after his repatriation to New Zealand had to be amputated.

[2] He represented New Zealand in the world One Ton yachting championships in Sydney in 1972 and sailed around Cape Horn the next year.

He was group general manager of Alex Harvey Industries, Auckland and served on the boards of AHI Aluminium and elsewhere.

He was a commentator on the flight, having replaced his close friend Sir Edmund Hillary, who was on a scheduled speaking tour of the United States.