James Robert Johnston (born 25 April 1980) is a Scottish bassist, vocalist, and songwriter, best known for his work with Scottish group Biffy Clyro.

Johnston was born and raised in Carmunnock, Glasgow before the family moved to Kilmarnock with his twin brother Ben (who became the drummer for Biffy Clyro), and his younger brother, Adam Johnston (who was Biffy Clyro's drum tech[1]).

The first gig he ever attended was Rancid at Glasgow Barrowlands in 1995, when he was fifteen.

Having previously played bass with schoolfriend Simon Neil and brother Ben Johnston in a band called Skrewfish in 1995,[2] the trio moved to Glasgow, and were soon discovered by manager Dee Bahl, and then signed to Beggars Banquet, in 2001.

Johnston's basses are usually tuned to Biffy Clyro's preferred tuning of (DADG), but sometimes (BADG) for "Pause it and Turn It Up" and (CGCF) for "Living is a Problem Because Everything Dies", as well as "That Golden Rule", "The Captain" and "Got Wrong".