In the 1920 season, Jardine made his first-class debut, played eight first-class matches and scored two fifties. Playing mainly as an opening batsman, he won his Blue, appearing in the University Match against Cambridge but fell short of expectations,[15] and continued to be criticised for over-caution with the bat. In all, he scored 217 runs at an average of 22.64.[23][24] In the match for Oxford against Essex, he took six wickets for six runs in a bowling spell of 45 balls, bowling leg breaks, to have bowling figures of six for 28.