On 31 July 1878, he married Margaret MacGregor Reid, daughter of his business partner Donald Reid. The marriage was conducted at Reid's residence Salisbury in North Taieri. They had four daughters, Fanny Stewart Fergus, Annie Grange Fergus (who became a doctor and served overseas during World War One) Daisy MacGregor Reid Fergus, Elizabeth (Bessie) Barr Fergus.bdmhistoricalrecords.dia.govt.nz
