Grant Heffernan worked in the Bank of New Zealand and the Post Office for several years before going to Brazil in 1982. In the initial years in Brazil, he worked as part of a GLO team in general missionary work. In 1987, he married Nilva, a Brazilian school teacher, and soon after they started a small intern Bible School in their own home. They ran this course over a period of about 15 years in the south-eastern part of Brazil in the state of Sao Paulo.

They returned to New Zealand and at the end of 2006 they took up ESOL teaching which they did over the next few years. Since 2012, commended by Northcross Community Church, they have been ESOL teaching  as a means of outreach in conjunction with an established church in Campinas in the state of Sao Paulo.

They have three children Melinda, Delano, and Katrina. Melinda is married to Hangyul Cho, assistant pastor at Northcross, and currently works for the Anglican Diocese in Parnell. Delano is studying Business Administration in Brazil, and Katrina is doing Biblical Studies at Laidlaw College in Henderson.