Stevenage defender Ryan Johnson trialed for Norwich in their Under-23s clash with Brighton on 24th April 2017, which finished 0-0.

Johnson started his career in the youth system of West Bromwich Albion, where he spent seven years as a schoolboy. In the summer of 2013, Johnson was offered a scholarship by the club but opted to leave and join Stevenage, where he felt he had a better chance of playing first team football. He made his professional debut in May 2014 in the 2–0 defeat to Brentford and became Stevenage's youngest ever debutant at the age of 17 years and 215 days. He had spent the October 2014 on a one month loan to Boreham Wood and the 2016/17 season on loan at St Albans City.

Shortly before joining Norwich on trial, he spent a week on trial with Tottenham.

Ahead of the 2017/18 season he joined Boreham Wood on a season long loan but it was curtailed in December 2018 after just two appearances at the start of the season. The following month he was loaned to Nuneaton Town.

He then joined Kidderminster Harriers for the 2018/19 season, this became permanent in January 2019. He left the club in April 2020. On 29th September 2020 he signed a short term contract with Hartlepool.

He has been capped by Northern Ireland at Under-21 level.