Donald Munro’s career began in 1938 when he first performed as a baritone in New Zealand. He then travelled to wartime London to study at the Royal College of Music, where he was awarded the prestigious Tagore Medal, awarded annually to the outstanding student of the year. He later went to Paris to study with the legendary baritone Pierre Bernac from 1946 to 1948. On his return to New Zealand, Munro began teaching in Dunedin and then Wellington, as well as performing many works including those of Douglas Lilburn.
Munro is celebrated for establishing New Zealand's first Opera Company in 1954. His primary goal was to "take opera to the people", ensuring that rural districts were visited as often as the city centres. Under his management, the Opera Company employed a Māori cast in the production of Porgy and Bess, helping to establish the careers of many Māori singers. As his career continued, Munro was involved in the production of many significant New Zealand works including Ngaio Marsh's A Unicorn for Christmas with music by David Farquhar, performed for the Queen during the Royal Tour of New Zealand in 1963. In 1960, Munro was awarded an MBE for his services to opera.
When his involvement with the New Zealand Opera Company ceased in the mid-1960s, Donald accepted an invitation to lecture at the University of Adelaide, where he became Dean of Music from 1974 to 1978. During this time he was appointed to various government arts funding bodies in Australia. Donald passed away shortly after his 99th birthday in 2012.