The 33-year old began his career as a youngster at Leicester City, making three senior appearances for the Foxes while taking in loans with Tranmere Rovers and Kettering Town.
A permanent move to Mansfield Town followed in 2011 where he enjoyed an eye-catching campaign, prompting Burnley to bring the right-back to Turf Moor in the summer of 2012.
Loans with York City, Southend United, Scunthorpe United and Leyton Orient followed prior to a permanent move to Southend in 2015 where he remained for two seasons.
O’Neill made the move to Kent in 2017 when he joined Gillingham, making 90 appearances for the Gills in League One over two seasons before signing for AFC Wimbledon in 2019, securing 64 appearances for Dons over two seasons in the third tier.
He rejoined Kettering in 2021 and represented Stevenage prior to a switch to Ebbsfleet United in 2022 where he has spent the last three campaigns, racking up 62 league appearances.
O’Neill joined his former Gills teammate Lee Martin at Park View Road as the Wings boss builds his squad for the 2025/26 season.