Wrexham-born Harrington spent three years at Everton's youth setup before being picked up by Scottish side Aberdeen, joining their U20 side before stepping into the reserve team. He then went on to enjoy a loan spell at Montrose in Scottish League One where he played 25 games before joining The New Saints in July 2019.

Harrington joined The Nomads in August 2021 following a two year spell at The New Saints. Harrington has also represented Wales at U19 and U17 level.

Ryan was a part of the team that won the JD Welsh Cup in 2024.