The 23-year-old sits atop the Rookie of the Year standings despite running a partial campaign that has consisted solely of road and street circuits. He has recorded three top-eight results in 11 IndyCar starts.
A former member of Ferrari's Driver Academy, Armstrong arrived in IndyCar after three years in Formula 2, winning four races and scoring a further four podiums from 2020-22.
His first taste on an oval will be at Texas Motor Speedway on 13 September.
“I am very proud and excited to continue with Chip Ganassi Racing for next year and beyond,” Armstrong said.
“Together with this very talented and experienced team, I am confident we can compete at the highest level in this championship. I feel very grateful that Chip has given me the time to adapt to IndyCar and has helped me every step of the way in what has been a good season.
“I’ve spent the year learning from a great group of people, including my team-mates and Dario [Franchitti]. I’m very grateful for how much help I’ve received from each team member.
“With a season under my belt, I now want to turn these lessons into results. I will be racing on the ovals for the first time next year and it’s an exciting challenge that I’m confident I can learn quickly.
“I spent the entire month of May either in the engineering office or in the pit stand this year, trying to familiarise myself with the details of oval racing. It’s a challenge that excites me a lot.”
Source: Autosport