Rojas has been capped at youth level by Colombia, Russia and England.
He told arsenal.com: “It’s an unbelievable feeling. I feel so proud of myself and happy with the work that I’ve done over the last few years. It’s always been my dream from such a young age to finally become a professional footballer.
"Now I’m here it continues motivating me to keep working hard every day to reach my goal of becoming the best goalkeeper in the world.
“Arsenal is a club that has a very rich history and I’ve become very fond of it. It’s strong in my heart and everybody here has always made me feel so welcome, from the coaching staff to the cleaners, the chefs, the security guards, the groundsmen that make everything possible for us so that I’m able to just focus on the football.
“My family have always been there for me, supporting me through the high and low moments and without their support I couldn’t be where I am today, especially my father. He’s been giving me advice and helping me train, especially during the lockdown that we had. I’m very grateful for everything that he’s done, I love him a lot and I love that he’s going to continue being on my journey with me."
Rojas also said: “Getting into the first team is the goal of any player, even moreso at a massive club like Arsenal. One of my goals is to become a Premier League player and play at the highest level, so there’s no better place to do it. I’ve got to continue working on the habits to make sure I’m the most consistent person on and off the pitch."