Career
While at school, Ahearne-Grant went to Football Club Barcelona for a trial. He later returned to England where he went on to play for the youth side of Charlton Athletic. Ahearne-Grant was top scorer for Charlton Athletic U18s during the 2012-2013 and 2013-2014 seasons while still a schoolboy.
Less than a week after his 17th birthday, on 23 September 2014, Grant signed a 3-year contract with Charlton.
He made his professional debut shortly after on 30 September 2014, as an 89th-minute substitute in a 1–0 victory against Norwich City. He later made his first start on 18 October 2014 in a 1–0 loss against AFC Bournemouth.
On 26 September, he scored his first league goal for Charlton in a 2-1 loss to Cardiff City. In February 2014 Grant represented England U17 in the Algarve tournament.
On 6 November 2014 Grant was called up to the England U18 squad for a double header against Poland.