After failing to secure a full-time drive in Formula One for the 2016 season, Rossi returned to the U.S. to compete in the IndyCar Series for a team with combined resources from Andretti Autosport and Bryan Herta Autosport. Rossi won the 2016 Indianapolis 500 and finished eleventh in series points. Rossi returned to Andretti in 2017 and added a second career win at Watkins Glen International for his first road course win in IndyCar. His 2018 and 2019 seasons were his most successful to date, finishing second and third in the Drivers' Championship point standings those years respectively.