Rivera was born at Beth Israel Medical Center in New York City, New York, the son of Lillian and Cruz "Allen" Rivera, a restaurant worker and cab driver respectively. Rivera's father was a Catholic Puerto Rican, and his mother is of Ashkenazi Russian Jewish descent. He was raised "mostly Jewish" and had a Bar Mitzvah ceremony. He grew up in Brooklyn and West Babylon, New York, where he attended West Babylon High School. Rivera's family was sometimes subjected to prejudice and racism, and took to spelling their surname as "Riviera" because they thought it sounded "less ethnic".

From September 1961 to May 1963, he attended the State University of New York Maritime College, where he was a member of the rowing team. In 1965, Rivera graduated from the University of Arizona (where he continued his involvement in athletics as a goalie on the lacrosse team) with a B.S. degree in business administration.
Following a series of jobs ranging from clothing salesman to short-order cook, Rivera enrolled at Brooklyn Law School in 1966. As a law student, he held internships with the New York County District Attorney under legendary crime-fighter Frank Hogan and Harlem Assertion of Rights (a community-based provider of legal services) before receiving his J.D. near the top of his class in 1969. He then held a Reginald Heber Smith Fellowship in poverty law at the University of Pennsylvania Law School in the summer of 1969 before being admitted to the New York State Bar later that year.

After working with such organizations as the lower Manhattan-based Community Action for Legal Services and the National Lawyers Guild, Rivera became a frequent attorney for the Puerto Rican activist group, the Young Lords, eventually precipitating his entry into private practice. This work attracted the attention of WABC-TV news director Al Primo when Rivera was interviewed about the group's occupation of an East Harlem church in 1969. Primo offered Rivera a job as a reporter but was unhappy with the first name "Gerald" (he wanted something more identifiably Latino) so they agreed to go with the pronunciation used by the Puerto Rican side of Rivera's family: Geraldo. Due to his dearth of journalistic experience, ABC arranged for Rivera to study introductory broadcast journalism under Fred Friendly in the Ford Foundation-funded Summer Program in Journalism for Members of Minority Groups at the Columbia University Graduate School of Journalism in 1970.

Geraldo started his reporter career from the city of New York.  He has also won many awards and accolades for performing his duties as a journalist.  This also includes the Kennedy award for journalism.  He has taken the interviews of many famous personalities which also includes late Michael Jackson.