Complex sentence: Gibbons had hired Ernest Calloway, an African-American organizer, who would work in the segregated mid-South for the Teamsters, and he hired Fisher on the recommendation of Calloway, who had been impressed by her work in Chicago.
Split into simpler sentences: Gibbons had hired Ernest Calloway, an African-American organizer, who would work in the segregated mid-South for the Teamsters. He hired Fisher on the recommendation of Calloway, who had been impressed by her work in Chicago.