The 18-year-old scored 13 goals in the academy set-up last season despite regularly playing above his age group in the under-21s, building on a breakout 2024-25 campaign before his following season was cut short by injury. Sunderland were determined to tie him down regardless, and Geragusian, who has already won his first cap for Armenia, ultimately chose to stay.
Academy manager John Hewitson said the club were delighted to have got the deal over the line.
"Finn has made massive progress over the last couple of seasons and that is testament to his hard-working attitude," Hewitson said. "We are delighted that he will be continuing his progression at the club."
Geragusian thanked those who had supported him at the Academy of Light and said he was hopeful of building on the experiences he has already had.
"I'm really proud of myself," he said. "The coaches and all the other staff have helped me out, and a big shout out to my family as well who have supported and pushed me this season. I've had some great opportunities and experiences, and hopefully now I'll be able to have many more this season."
Manager Regis Le Bris, speaking in April about the striker's progress, struck a note of caution alongside his praise, stressing that first-team involvement would need to be earned in time rather than rushed.
"It's a good sign to have young players playing for their country, especially after such a long period in the third level of the league," Le Bris said. "You can't invest the same level of money, so it means you have to work hard, and if you provide the right environment then the players can grow. It's a bit early at the minute for Geragusian to be playing in the Premier League.
"Often the best period to start playing with the squad is pre-season. Now he's training regularly with us but the competition is high, especially in this position. He's learning. It's important he's connected with the squad but he'll have to wait for opportunities."
Geragusian's decision to commit his long-term future to Sunderland comes at a significant moment for the club's academy, with the striker regarded as one of the most promising forwards to emerge from the Academy of Light in recent years. Fending off interest from a club of Rangers' stature underlines the esteem in which he is held.