[1][2] Ian Brooker was born in Adelaide, South Australia on 2 June 1934.
[2] He worked with the Soil Conservation Branch of the Department of Agriculture in South Australia from 1957 to 1963; then joined the Department of Botany at the Australian National University until 1969; and then spent a year with the Western Australian Herbarium.
In 1970, Brooker joined the Forest Research Institute in Canberra, now part of CSIRO.
In his role as a eucalypt specialist, he travelled widely in the world, including the US, Brazil, most European countries, southern and eastern Africa, Morocco, Israel, India, China, and New Zealand.
In 1980/1981 he was appointed Australian Botanical Liaison Officer at Kew in the UK.