...Kool Herc is a New Yorker, a citizen of the United States. He adopted the customs and culture of New York, none of his contributions reflected Jamaican culture.
While growing up in Kingston he saw and heard the sound systems firsthand at neighborhood parties called dancehalls. He moved to the Bronx, New York at the age of 12 and began to throw free neighborhood parties.
He is also well known for his massive, high-quality, high-volume sound system, against which even superior DJs could not compete. Herc first used reggae records and was toasting to the music like Jamaican artists U-Roy and I-Roy. But he started using funk records due to popular demand.
http://www.cincystreetdesign.com/1520_Sedgwick/
As was said in OP. in 1950s Jamaica DJs would travel the island setting up neighbourhood parties for the poor