McPherson gained his first cap for Scotland in 1920 against Wales at Inverleith alongside teammate Dr E Fahmy, who also played his club rugby in Wales. Scotland won 9-5, and prevented Wales from winning the Grand Slam. After accepting a gold watch as part of Newport's invincible 1922/23 season, the Scottish Rugby Union suspended McPherson for what they saw as an act of professionalism; but he was later re-instated. McPherson's last game for Scotland was against Ireland, but was chosen to join the British Lions 1924 tour of South Africa, when he played in all four tests against the Springboks.