On 12 October 1944, Frank Sinatra opened his third season at New York's Paramount theatre. It was Columbus Day, a public holiday, and the bobby-soxers turned out in force. The famed New York photographer Weegee (Arthur Fellig) was there with his camera and notebook, capturing the scene in hyperventilated prose.

"Oh! Oh! Frankie," he began, mimicking the girls' ululations. "The line in front of the Paramount theatre on Broadway starts forming at midnight. By four in the morning, there are over 500 girls … they wear bobby sox (of course), bow ties (the same as Frankie wears) and have photos of Sinatra pinned to their dresses …

"Then the great moment arrived. Sinatra appeared on stage ... hysterical shouts of 'Frankie ... Frankie'; you've heard the squeals on the radio when he sings. Multiply that by about a thousand times and you get an idea of the deafening noise."

For Weegee, this was another example of the human extremities that he documented with his instinct for the climatic moments in New York life: what he didn't mention was the fact that, after each performance, the Paramount was drenched in urine.

Like Rudolph Valentino's funeral in 1926, or The Wizard of Oz opening in 1939, the Columbus Day riot was a generation-defining media event acted out on Manhattan's streets: during the day some 30,000 frenzied bobby-soxers swarmed over Times Square in an exhilarated display of girl power.

The New Republic editor Bruce Bliven called it "a phenomenon of mass hysteria that is only seen two or three times in a century. You need to go back not merely to Lindbergh [Charles Lindbergh's first flight] and Valentino to understand it, but to the dance madness that overtook some German villages in the middle ages, or to the Children's Crusade." What was new was the power that one singer held, heralded by mass screaming, and the advent of the teenager as a social ideal. Sinatra was the first modern pop star.

Sinatra's fame had been steadily building. His breakthrough came in his first Paramount season in December 1942, when the theatre erupted with "five thousand kids stamping, yelling, screaming, applauding". These scenes only intensified during his return in May 1943. The mania overtook the hype: his press agents remembered hiring "girls to scream when he sexily rolled a note. But we needn't have. The dozen girls we hired to scream and swoon did exactly as we told them. But hundreds more we didn't hire screamed even louder. It was wild, crazy, completely out of control."

Although nearly 29 by October 1944, Sinatra was slightly built, nervous and youthful: "It was the war years," he later said, "there was a great loneliness. I was the boy in every corner drugstore, the boy who had gone to war."

In concert, he seduced his young audience. His bright blue eyes raked the crowd, singling out individuals so that he appeared to be singing for them alone, just one in a crowd of thousands. Matched to the ethereal kitsch of slow ballads such as Embraceable You, "The Voice" – as Sinatra was known – cast a spell that suspended time.

Sinatra's rise was unstoppable, for he filled a deep need. Bliven thought that the bobby-soxers at the Paramount "found in him, for all his youthfulness, something of a father image. And beyond that, he represents a dream of what they themselves might conceivably do or become."

In the mid-40s, Sinatra became a national figure of controversy and criticism. He was blamed for making young people lose "control of their emotions", and was attacked for being out of uniform: because of an injury, he had been ruled unfit for duty in 1943.

Yet his status was confirmed in September 1944 when he went to the White House and met the president. Franklin Roosevelt had already made public statements linking American politics with its popular music, but this meeting was a shrewdly taken opportunity to reaffirm that adolescents were a vital part of American society.

The Columbus Day riots coincided with the invention of the teenage market. In September 1944, the magazine Seventeen was launched, which declared to its primarily female readers: "you are the bosses of the business". It was an immediate success, selling half a million copies. Seventeen offered a non-patronising approach that struck a chord, and it focused Americans on the barely recognised purchasing power of adolescents: estimated at $750m (£465m).

The hysteria that surrounded Sinatra in October 1944 came at a crux time in the history of America and its youth. It reaffirmed the collective power of young women, and how they have always been central to pop.