Alonso, who turns 39 later this month, has been out of the sport since he appeared to bring down the curtain on his career with McLaren 18 months ago.
But the Spaniard, who won successive championships with Renault in 2005 and 2006, has now completed a sensational comeback with the French manufacturer.
“In addition to past successes, it is a bold mutual choice as well as a project for the future.
“His experience and determination will enable us to get the best out of each other to take the team towards the excellence that modern Formula 1 demands.
“He will also bring to our team, which has grown very fast, a culture of racing and winning to overcome hurdles together.
“Alongside Esteban, his mission will be to help Renault DP World F1 Team prepare for the 2022 season in the best possible conditions.”