Patrick Kelly joined West Ham United on a three-year professional deal from NIFL Premiership club Coleraine in July 2022.

Kelly made himself a regular in the West Ham United U18s since his move and earned his first appearance for the U21s in an EFL Trophy group stage win at Walsall on 30 August 2022, before making his first Premier League 2 appearance away to Manchester City a few days later.

The Northern Irish midfielder enjoyed a positive 2022/23 season with Kevin Keen’s U18s, featuring 19 times for the side across all competitions. Kelly played a key role in the side’s historic double as the young Hammers won the FA Youth Cup and the U18 Premier League South.

In 2023/24, Kelly played a key role in the young Hammers' successful campaign which saw them finish second in the Premier League 2 regular season and reach the EFL Trophy round of 16. He also appeared in all ten of Northern Ireland U21s' UEFA European U21 Championship qualifiers against Luxembourg, Ukraine, Azerbaijan, Serbia and England.

Summer 2024 saw Kelly loaned to EFL League Two club Doncaster Rovers, for whom he made a league debut in a 3-1 defeat at Newport County on 17 August. Ten days later, he started as Doncaster played at Premier League Everton in the EFL Cup second round, losing 3-0. Kelly then scored on his FA Cup debut in a 1-0 first-round win at Barrow on 2 November, then netted a maiden league goal in a 3-1 win at Tranmere Rovers on 21 December.