For the 2000 season, Penske stopped building cars, switched to a Reynard 2Ki, changed engine manufacturers from Mercedes-Benz to Honda, and tire supplier from Goodyear to Firestone in a bid to improve performance. Castroneves found the Honda engine's driveability different than Mercedes-Benz's, and was at first, not friends with his teammate de Ferran because they were competitors. He finished second at the Grand Prix of Long Beach, his only points finish in the first six races. He led the final 24 laps of the Grand Prix of Detroit in his first series victory after Juan Pablo Montoya retired with mechanical trouble. Castroneves won the Miller Lite 200 at Mid-Ohio Sports Car Course, and took five top-tens and a third victory in the Grand Prix of Monterey at Laguna Seca. He was seventh in the drivers' championship with 129 points, and was named the inaugural winner of the Greg Moore Legacy Award as "the driver who best typifies Moore's outstanding talent on the track as well as displaying a dynamic personality with the fans, media and the CART community."
After winning a race, Castroneves celebrated by stopping his car, and climbing the catchfence to send a message of delight in achieving success. He began the tradition with his first CART victory in Detroit in 2000 and repeated it each time he won a race. After this celebration, John Kernan, host of RPM 2Night, first gave Castroneves the nickname "Spider-Man", and has been mimicked by other drivers in the following years. His photogenic looks have been picked up the press, Including People, ESPN The Magazine, and Cosmopolitan. Castroneves has done business with oil companies Pennzoil, Shell, and electronics company SMS Audio. In December 2004, he had an audience with Pope John Paul II and spoke to a congress on how Catholicism impacted his life and racing career. Castroneves won the 2001 Indianapolis 500 Rookie of the Year and the 2004 Scott Brayton Award for "displaying the character that best exemplifies the racing spirit of the late Scott Brayton." He was inducted into the Indy Lights Hall of Fame in 2014 as a 1997 graduate, and the Texas Motorsports Hall of Fame in November 2018.