Macrae is the son of the Revd Donald and Anne Macrae. He was born in Melbourne and spent most of his childhood in Sale, Victoria, before moving to Melbourne for secondary education and then Melbourne University.
He has degrees in arts, theology and philosophy from the University of Melbourne and the University of Dublin.
Macrae was ordained in 1984 and has served in rural, regional and inner city congregations in Victoria, at Mt Beauty, Portland and West Brunswick. He served as Moderator of the Synod of Victoria and Tasmania (2000–2003) and as Executive Director of the Uniting Church Centre for Theology and Ministry (2004–2009) in that synod. He was a member of the board of Wesley Mission Melbourne and chaired its social policy committee.
Macrae was an inaugural member of the Victorian State Government's Community Support Fund and served on the advisory committee of the Community Alcohol Action network of the Australian Drug Foundation.
Macrae became President of the UCA in July 2009, at the 12th Assembly. His theme for the three years of the assembly was "Living Water, Thirsty Land", a metaphor inspired by a photo of a 4WD utility published in The Age newspaper. Two young people were found dead under their ute in outback Australia having run out of petrol and then water. Afterwards, local Indigenous people said if the travellers had known where to look they would have found life-giving water within 200 metres of where they were stranded.
In September 2013 Macrae commenced as Minister of Wesley Uniting Church, Lonsdale Street, Melbourne.
Macrae is married to Clare Boyd-Macrae, a writer, and they have four children, Tess, Patrick, Hamish and Fiona. His interests include sport of most kinds, notably Australian Rules football as well as cooking, reading, running, renovating, gardening and being with family and friends.
In 2017 Macrae was appointed an Officer of the Order of Australia for distinguished service to the Uniting Church in Australia through executive and ministerial roles at state and national levels, and to the promotion of ecumenism, interfaith dialogue and reconciliation.