He is the younger brother of Ryhan Stewart, who is also a professional footballer currently playing for Singapore Premier League club, Albirex Niigata (S).

[3] He made his official debut coming on as a substitute during a league match against Uthai Thani in a 1–1 draw on 11 February.

On 21 March 2024, Harhys made his debut for Singapore in the 2026 FIFA World Cup qualification match against China.

[4] His older brother, Ryhan Stewart, is also a professional footballer who plays primarily as a right-back for Singapore Premier League club Albirex Niigata (S).

Harhys previously lived in the United Arab Emirates and Finland, before eventually returning to his home country of Singapore.