He came through the Glamorgan academy and was named in their team to play against Cardiff MCCU in a pre-season match in April 2022.
[2] He was then included in the squad for Glamorgan's first three games of the Twenty20 season in 2023, against Gloucestershire, Somerset and Middlesex.
[5] He played in the four-wicket defeat to Somerset two days later, scoring just one run off four balls with the bat, and conceding 10 runs off his single over of bowling, though he did take a catch.
[8] With several senior Glamorgan players having been called up to play in The Hundred or simply rested, Kellaway returned to action in the opening match of Glamorgan's 2023 One-Day Cup campaign against Worcestershire.
[9] Coming in with Glamorgan at 72/4, he shared a stand of 65 runs with captain Kiran Carlson and eventually top-scored with 82 runs as they finished with a total of 199; however, Worcestershire chased down the target to win by four wickets, Kellaway conceding 18 runs off his four overs.