Sordo, who has over 20 years of engineering experience in Formula 1, will join the team co-owned by Bobby Rahal, David Letterman and Mike Lanigan on October 1.
Sordo spent the past six seasons with McLaren Racing F1 as head and director of vehicle performance and, prior to that, spent 10 seasons with Red Bull Racing as an aero performance team leader, then head of aero performance. Before that, Sordo enjoyed spells as race engineer at RBR, at what was then called Scuderia Toro Rosso, at Jaguar Racing and at Arrows.
RLL's statement today states that Sordo will now "oversee a multi-tiered engineering structure at the team's new headquarters in Zionsville, Indiana that will have an emphasis on a variety of areas and lay the foundation for the team to achieve their goals."
Sordo described IndyCar as "a very challenging and very competitive series where I think every competitor can have a chance at winning every time they participate in a race, providing you get all the ingredients right.
"The excitement of this new role for me is to challenge myself and see if with the experience and methodology developed through many years spent in F1 I can help the team moving forward in becoming a consistent front-running team. This is the clear challenge and target that I set for myself and I look forward to getting started.
"I would like to thank Bobby and Mike for this opportunity and their trust in my abilities and I hope I can repay them with successes at the track."
Rahal commented: "I'm so pleased that Stefano will be joining the team as technical director. He is well respected in the industry and his track record speaks for itself having worked with organizations like McLaren and Red Bull in Formula 1, among others.
"I'm confident that Stefano will bring to us a perspective that will raise our game against our competition and work well with our existing engineering staff."
Added Lanigan: "Stefano has shown he is capable of leading large groups of engineers at the top level of motorsport and we couldn't be more pleased to have him join our team.
"His depth of experience, combined with his knowledge of the various areas to maximize the performance of a race car will be a tremendous asset to us going forward."
