Born in Christchurch, New Zealand on 29th July 2000, Marcus Armstrong started karting in 2010. One year on from his debut, he took his first win in the National Championship.
In 2012, Marcus came fourth in the Rotax Festival Asia, at his first participation in an international event. In 2013, he finished third in the Shifter Kart USA Super Nationals and in 2014, he took part in the New Zealand Formula Ford Championship. Following an evaluation test at the Fiorano Circuit in October, Marcus joined the FDA. In 2017, he won the Italian F4 series with the Prema team and finished second in the German F4 series.