The announcement came exactly sixty minutes after the Woking outfit revealed that Stoffel Vandoorne would be leaving the team at season end.
Norris, 18, from Somerset, McLaren's test and reserve Driver and is currently second in the Formula 2 Championship, having won on his Formula 2 debut from pole position, with four races from two events remaining.
He has been part of the McLaren Young Driver Programme since early 2017, when he officially joined the team as test and simulator driver. Since then, he has regularly conducted race simulation work for the team and also participated in Formula 1 testing – in Abu Dhabi in 2017, and Spain and Hungary in 2018. Most recently, he has driven in the first free practice sessions in both Belgium and Italy.
In his early career prior to joining McLaren, Norris rose rapidly through the ranks in junior racing categories, winning the Formula Renault 2.0 Northern European Cup, Formula Renault 2.0 Eurocup and the Toyota Racing Series Championship all in 2016, in addition to five karting championships in the four previous years. Last year, he contested the European Formula 3 Championship, which he won at the first attempt.
"We're very pleased to finally be able to reveal who will complete our driver line-up at McLaren for 2019," said Zak Brown. "We believe Lando is an exciting talent, full of potential, who we've very deliberately kept within the McLaren fold for exactly that reason.
"We already know he's fast, he learns quickly, and has a mature head on his young shoulders. We see much potential for our future together. The investment we have made in his budding career with simulator development and seat-time in the car has been well-deserved, as he has continued to prove his abilities both behind the wheel and in his work with the engineering team.
"Lando is an integral part of our plan for rebuilding our Formula 1 operation for the future, and he has already developed a strong relationship with the team.
"In Lando and Carlos we have an impressive duo who, despite their relative youth, hold valuable experience in Formula 1 and with McLaren, and represent the next generation of McLaren drivers to lead the team forward. While our short-term focus is fixed on securing the best possible result for the remainder of the 2018 season, we're also massively motivated by the opportunities that lie ahead."
"To be announced as a race driver for McLaren is a dream come true," said Norris. "Although I've been part of the team for a while now, this is a special moment, one I could only hope would become reality.
"I'd like to thank the whole team for this amazing opportunity and for believing in me. I'm also extremely grateful for the commitment McLaren has already shown in my development, allowing me to build my experience in a Formula 1 car in both testing and on Fridays during the past two race weekends.
"For the remainder of 2018, my focus remains firmly on the Formula 2 championship. My objective is to win the title before joining McLaren full-time, which will be tough, but I will fight as hard as I can for the remaining four races. I'll also be working closely with McLaren at every opportunity to learn as much as possible from the drivers, engineers and mechanics to give myself the best preparation ahead of next year."