Think Kerouac and the beats.
But they didn't use call themselves "hippie" and they weren't pervasive. I lived in Berkeley during the "Bohemian" years (artistic, very few in number, oddities that the normal people thought were fun to 'people watch', hung out in a couple of coffee shops on the north side of campus, perhaps numbered a hundred, or so altogether). The Bohemians were followed by the Beatniks, who were a little scarier, but their numbers were not that much greater. They began to make their presence felt on the south side of campus. They were more agressive, compared to the earlier bohemians.
The Free Speech Movement started in 1964 and was a shock to the entire Bay Area community. They shut down Sproul Plaza -- the area where people traditionally hung out and made speeches. Many arrests. Demonstrations lingered on for days. Mario Savio trapped in a police car.
But none of these groups (until the FSM) were overt about challenging the morals and mores of the time. There may have been an out of wedlock pregnancy here and there and funny clothes, but they were not spouting 'free love', drugs, etc. Until the 'hippie' generation which started in 1967 when Barry Soetero was already in kindergarten in Jakarta.
Stanley Ann Dunham Obama Soetero was definitely before her time in behavior!