Mears captured three wins competing for Team Penske in 11 of the 18 USAC Championship events of 1978, so for 1979, Roger Penske hired him for what would be Mears’ first full-time season.  Team Penske introduced the PC7 chassis for the 1979 campaign, with teammate Bobby Unser performing most of the chassis’ development testing. Before May, Penske asked Mears which chassis he wanted to use for the "500," and he chose the year-old PC6, as he was more familiar with that car. Mears was fast all month and qualified on pole position—his first career pole at IMS. The Unser brothers, Al and Bobby, dominated the first part of the "500," with Al leading a majority of the laps in Jim Hall's aerodynamic wonder, the Chaparral 2K. Transmission problems ended Al's race, however, allowing Bobby to take the lead with the new PC7. Mears was in second place when Bobby lost his top gear with 20 laps remaining. Mears passed his teammate, capturing his first Indianapolis 500 victory. He enjoyed more success with two additional victories and secured his first Championship Auto Racing Teams (CART) series championship.