Johnville began his career at Leyton Orient before leaving for Stoke City at 15 years old. He spent four years at The Potters before joining AFC Wimbledon in League 2. Comfortable in both defence & midfield, he spent six months at Maldon & Tiptree last season. Johnville made his Stortford debut against Hitchin Town in a Herts County Charity Cup tie in August 2018 and netted his first Blues goal in a 4-3 defeat at home to Tonbridge Angels in January. By the end of last season Johnville had played 51 times for Stortford and netted 3 goals.