In 1997 he made his Indy Racing League debut driving for Thomas Knapp in an unsponsored black #97 car.
The car attracted sponsorship from local businesses and the national anti-tobacco campaign, and became known as Ash Kicker Racing.
In 2001 Ray and Menard had split, and his replacement Jaques Lazier won his first victory at the Chicagoland Speedway.
He gained sponsorship from TrimSpa but failed to light up the scoreboard and in 2004, he ran a few races before giving his seat to former Infiniti Pro Series champion Mark Taylor.
Greg Ray made his debut Indy Racing League start during the 1997 portion of the 1996-97 Indy Racing League season driving the #97 Thomas Knapp Motorsports Dallara-Oldsmobile Aurora in 5 of 10 events including the Indianapolis 500 where he would finish 25th due to a water pump failure.
Ray would manage to qualify second between A. J. Foyt Enterprises teammates Billy Boat and Kenny Brack and would gain race day sponsorship from Justice Brothers, Inc., True Value, The Nashville Network, and Ray's hometown track Texas Motor Speedway.
Knapp's team then closed its doors for good due to a lack of sponsorship but Ray was signed on to drive the #2 Glidden/Menards Dallara-Oldsmobile Aurora and would take pole positions at the MCI WorldCom 200 at Phoenix International Raceway and the VisionAire 500K at Lowe's Motor Speedway (the latter of which was cancelled due to an accident that killed three spectators).
Ray would retire from the first three races before getting three wins at Radisson 200 and Colorado Indy 200 Presented by Deloitte & Touche both at Pikes Peak International Raceway and the MBNA Mid-Atlantic 200 at Dover Downs International Speedway to get the championship (Ray's only time in the top 10 in points).
Ray would drive the season ending Chevy 500 at Texas Motor Speedway returning to A. J. Foyt's team in the #11 A. J. Foyt Racing Dallara-Nissan Infiniti where Ray would start 13th and finish 8th in his only other top 10 of the year besides his Atlanta win.
Starting off 2002 without a ride Ray was hired to drive the #11 Harrah's Dallara-Chevrolet for A. J. Foyt Enterprises in place of the injured Eliseo Salazar.
Ray would then drive for Sam Schmidt Motorsports in the #20 Dallara-Chevrolet with sponsorship from Empress Casino and Young Chevrolet in the final two races of the season.
Ray acquired sponsorship from Renovac for the opening rounds on his #13 Panoz G Force-Honda and would have a 2nd place start at the Indy Japan 300 at Twin Ring Motegi.
But soon a lack of sponsorship caught up to Ray as he had to withdraw from the following race, the Argent Mortgage Indy 300 at Kansas Speedway.
In that season Ray had 7 podium finishes and set a track record lap for a Formula Ford 2000 car at Sears Point Raceway and would take the series championship.