The League's premier series debuted in 1996 under the name Indy Racing League. The series adopted the name Indy Racing League IndyCar Series in 2003. With Verizon as corporate sponsor from 2014 through 2018, the series has been known as the Verizon IndyCar Series. On January 15, 2019, it was announced that NTT Corporation (Nippon Telegraph and Telephone) would become the title sponsor and the series will become the NTT IndyCar Series.
The series initially raced exclusively on oval tracks, as the series was founded partly in response to the increasing prominence of road and street courses on the CART schedule. In 2005, the series abandoned its unofficial ovals-only stance, and added three road–street course events. By 2009, the series had a roughly 50/50 split of ovals and road/street courses. Presently, the series currently runs one-third of its schedule on ovals and the rest on road and street circuits.