Acts that performed at the festival in order of appearance:
Deep Purple's performance was one of the first with their third line-up, which included the vocalist David Coverdale and the vocalist/bassist Glenn Hughes. Deep Purple was given the choice of when to go on stage, and chose to go on during sunset, thus pushing Emerson, Lake & Palmer to the last performance. Assuming that, as with all festivals, the show would run late anyway, they still waited when the festival was actually ahead of schedule. Angry concert organizers tried to force Deep Purple to go onstage, and then threatened to cancel their performance. A quick thinking announcer told the crowds that Deep Purple would be coming on "soon". The band made concertgoers wait nearly an hour until near dusk before they went on stage. Richie Blackmore, the Deep Purple lead guitarist, has said the concert agreement at Cal Jam was always for Deep Purple to go on stage at dusk, and concert promoters were in violation of a signed agreement. In spite of this delay, the show did not end up running late. At the end of their concert, guitarist Ritchie Blackmore threw a guitar, and a small speaker monitor out into the audience, and suddenly attacked one of the network's video cameras (the camera had been getting between Blackmore and the audience) with a guitar. Later on, a mishap with a pyrotechnic effect caused one of Blackmore's amplifiers to explode, which briefly set the stage on fire. Deep Purple left the concert area by helicopter to avoid a possible confrontation with Ontario fire marshals and ABC-TV executives. The damage to the ABC video camera was estimated to be $10,000, later settled by the band managers.
The weather on the day of the Cal Jam concert was unusually warm for April. At one point in the late afternoon, thousands of plastic gallon jugs were handed out to the audience, who were able to fill the jugs up at the many drinking fountains set up on the grounds. During the prolonged delay waiting for Deep Purple to hit the stage, restless concert goers began tossing their water jugs in the air. More and more of the audience joined in, until the air above the crowd was filled with hundreds of water jugs flying around, spraying water over the audience.
Deep Purple's California Jam performance, along with some of the performances by other bands, was broadcast on TV and radio nationwide in the US. It was at this festival that the footage of Keith Emerson playing a grand piano spinning end-over-end 50 feet above the ground was taken.