The band were introduced on the Main Stage by a huge, dancing rabbit with the name of drummer Tre Cool on its back.
After starting their set with '99 Revolutions', frontman Billie Joe Armstrong picked a fan from the crowd and brought him on stage to sing 'Know Your Enemy'.
The band played the entirety of their third album, 1994's Dookie, in between some of their biggest songs including 'Holiday' and 'Wake Me Up When September Ends'.
For 'St Jimmy', Armstrong sprayed the audience with a big water gun. He later used another gun which fired T-shirts at the crowd.
Following 'American Idiot' and 'Jesus of Suburbia', Armstrong - who called Reading "the greatest festival in the world" - closed Green Day's set with his acoustic guitar for 'Good Riddance (Time Of Your Life)'.
Eminem and Biffy Clyro are also headlining Reading Festival this weekend (August 24-25), with further performances from Nine Inch Nails, Fall Out Boy and Chase & Status.
Photo gallery - Reading and Leeds Festival 2013:
Copyright: Yui Mok/PA Wire/Press Association Images