Mooney, 18, has made 23 appearances in all competitions for St Mirren since making his senior debut at the beginning of the 2024/25 campaign.
Advertisement
Advertisement
He will initially be registered with Arsenal's U21 team.
A product of St Mirren’s academy, capable of playing in attacking midfield or as a centre-forward, Mooney's league debut came in October 2024 in a defeat to Hearts.
A Scotland youth international, Mooney has made six appearances at under-19 level for his country.