Groden attended Forest Hills High School in Queens, New York, leaving in the 11th grade. He served in the Army starting in 1964, and first became interested in the JFK assassination that same year. A harsh critic of the Warren Commission, he also testified at the 1975 United States President's Commission on CIA activities within the United States (sometimes referred to, improperly, as the Rockefeller Commission).

Groden testified at the O.J. Simpson civil trial, that he has no formal photography training and that is not certified by any professional photography organizations nor knows the names of such organizations. He has never taught any photography classes, nor has he published anything with respect to photography.

Groden achieved his first national exposure when on March 6, 1975 he and Dick Gregory were on Good Night America, a late-night TV program hosted by Geraldo Rivera, and they showed Groden's copy of the 27-second home movie captured by Abraham Zapruder of the Kennedy assassination. It was the first time, ever, that the movie was shown in motion to a national TV audience.

He was a consultant for Oliver Stone's 1991 film JFK, even appearing in two brief cameo roles as a Parkland doctor working to save the President, and, as the courtroom projectionist showing the Zapruder film during the Clay Shaw trial in New Orleans.

As well as his own publications, Groden co-authored with F. Peter Model, the book JFK: The Case for Conspiracy and with Harrison E. Livingstone the book High Treason: The Assassination of President John F. Kennedy & the Case for Conspiracy (also referred to as High Treason I).

During the O.J. Simpson civil trial, Groden appeared as an expert witness and testified that a 1993 photograph of Simpson wearing Bruno Magli shoes at a NFL football game was a forgery. Even after thirty additional photos by a different photographer captured on the same day of Simpson wearing the same clothes and shoes surfaced, Groden still maintained that the original photograph was a forgery. During his cross-examination on December 18, 1996, Mr. Groden was asked under oath: "Do you have any formal training in photography?" - Mr. Groden answered: "No" (See http://mcadams.posc.mu.edu/groden1.htm for transcript of testimony).

Groden sued Random House over a 1993 New York Times advertisement for Gerald Posner's book Case Closed where Groden was featured along with other conspiracy theorists and declared "guilty of misleading the American public." The U.S. District Court issued a summary judgment and dismissed the case.

Groden can also be found on many days of the week in Dealey Plaza up on its north grassy knoll, where he freely discusses his research and thoughts about the assassination and sells his books and videos. He was arrested on June 13, 2010 for selling merchandise in Dealey Plaza without a permit and has since filed a federal lawsuit against the City of Dallas as a result of the arrest (http://blogs.dallasobserver.com/unfairpark/2010/06/robert_groden_files_federal_su.php)