McFarland's grandfather, Danny, came from Belfast, and played rugby for Queen's University before becoming an engineer, working on coal-fired and nuclear power stations in England.
[1] McFarland attended Ampleforth College, North Yorkshire, where he started playing rugby,[1] and studied classics at Newcastle University.
[11] In 2015 he took over from Shade Munro as assistant coach at Glasgow Warriors, shortly after the club won the Pro12 for the first time.
[13] After the resignation of Jono Gibbes as Ulster's head coach at the end of the 2017–18 season, McFarland was announced as his replacement on 30 April 2018.
Initially he was to serve his notice with Scotland and join Ulster in January 2019, with Simon Easterby to act as interim head coach until then.
[19] In 2021–22 they made the semi-finals of the United Rugby Championship and the round of 16 in the Champions Cup, and McFarland signed a new contract at the end of the season.