Given that Kennedy was President of the United States, and his murder was investigated by several government agencies, it is obvious that a large number of government officials played some part in the assassination story. Here is a sampling of a few of the more important players:
J. Edgar Hoover - The legendary FBI Director took early control of the assassination investigation, and the FBI was the primary investigative arm of the Warren Commission.
Nicholas Katzenbach - Assistant Attorney General under Robert Kennedy, Katzenbach wrote a memo on 25 Nov 1963 asserting that "the public must be satisfied that Oswald was the assassin."
Lyndon Johnson - The new President initially resisted calls for a "blue ribbon commission," but then appointed one a week after the assassination.
Robert Kennedy - The slain President's own brother was Attorney General of the United States, but played no active role in the investigation.
Earl Warren - After turning down the job several times, Chief Justice Earl Warren was convinced by Lyndon Johnson to head a President's Commission at an Oval Office meeting where World War III was raised.
James Angleton - Head of CounterIntelligence at the CIA, Angleton's division opened a file on Lee Oswald in 1960. The CI division intersects with Oswald and the assassination investigation at many points.
There are many many more names of interest - use the search engine to locate information about them:
White House: McGeorge Bundy, Lyndon Johnson, Malcolm Kilduff, Godfrey McHugh, Kenneth O'Donnell, David Powers, Pierre Salinger.
Justice Department: Ramsey Clark, Nicholas Katzenbach, Robert Kennedy, Barefoot Sanders.
Dallas Police & Texas Authorities: John Adamcik, William Alexander, Marrion Baker, Eugene Barnett, Charles Batchelor, Paul Bentley, Eugene Boone, George Butler, Earle Cabell, Waggoner Carr, Bob Carroll, James Chaney, Roger Craig, Jesse Curry, J.C. Day, Patrick Dean, Bill Decker, Will Fritz, L.C. Graves, Gerald Hill, Bobby Hargis, D.V. Harkness, Clyde Haygood, William "Blackie" Harrison, Harry Holmes, Murray Jackson, Winston Lawson, James Leavelle, George Lumpkin, B.J. Martin, M.N. McDonald, H.B. McLain, Louis Miller, Luke Mooney, Joe Murphy, Harry Olsen, Bobby Patterson, J.M. Poe, Jack Revill, Earl Rose, Guy Rose, J. Herbert Sawyer, Joe Marshall Smith, Richard Stovall, H.W. Summers, Allan Sweatt, Cecil Talbert, Tom Tilson, J.D. Tippit, Roy Vaughn, Henry Wade, Eddy "Buddy" Walthers, Harry Weatherford, Seymour Weitzman, W.R. Westbrook.
FBI: Alan Belmont, James Cadigan, Cortlandt Cunningham, Warren deBrueys, B. Thomas Carter, Cartha DeLoach, Vincent Drain, John Fain, Mark Felt, Robert Frazier, John Gallagher, Carver Gaten, Robert Gemberling, Bill Herndon, J. Edgar Hoover, James Hosty, Milton Kaack, Regis Kennedy, Charles Killion, Sebastian Latona, James Malley, Bardwell Odum, Francis O'Neill Jr., Nat Pinkston, John Quigley, Lyndal Shaneyfelt, Gordon Shanklin, James Sibert, Paul Stombaugh, William Sullivan, Clyde Tolson, William Walter.
CIA: James Angleton, Tracy Barnes, Richard Bissell, Charles Cabell, Sheffield Edwards, Ann Egerter, Desmond Fitzgerald, Anne Goodpasture, Sam Halpern, William Harvey, Richard Helms, Lawrence Houston, E. Howard Hunt, George Joannides, Thomas Karamessines, J.C. King, Victor Marchetti, John McCone, J. Walton Moore, David Phillips, Raymond Rocca, Jane Roman, Win Scott, John Whitten, James Wilcott.
Secret Service & Treasury Department: Gerald Behn, Glenn Bennett, Lane Bertram, Abraham Bolden, Robert Bouck, Frank Ellsworth, Leon Gopadze, David Grant, William Greer, George Hickey, Clint Hill, Thomas "Lem" Johns, Roy Kellerman, Thomas Kelley, Samuel Kinney, Paul Landis, John Ready, Emory Roberts, James Rowley, Forrest Sorrells, Rufus Youngblood.
State Department: Abram Chayes, John McVickar, Dean Rusk, Carroll Seeley, Richard Snyder.
Defense Department: William Bishop, Larry Huff, Curtis LeMay, Robert Jones, Fred Korth, Lyman Lemnitzer, Robert McNamara, L. Fletcher Prouty, Carson Roberts, David Shoup, James Swindal, Edwin Walker, George Whitmeyer, Charles Willoughby.
Warren Commission: Francis Adams, Joseph Ball, David Belin, Hale Boggs, William Coleman, John Sherman Cooper, Allen Dulles, Melvin Eisenberg, Gerald Ford, Alfred Goldberg, Burt Griffin, Leon Hubert, Albert Jenner, Wesley Liebeler, John McCloy, Richard Mosk, J. Lee Rankin, Norman Redlich, Richard Russell, David Slawson, Arlen Specter, Samuel Stern, Earl Warren.
Church Committee: Howard Baker, Frank Church, Gary Hart, Richard Schweiker.
HSCA: Michael Baden, G. Robert Blakey, Gary Cornwell, Christopher Dodd, Thomas Downing, Ida Dox, Walter Fauntroy, Gaeton Fonzi, Henry Gonzales, Dan Hardway, Jacqueline Hess, Edwin Lopez, Richardson Preyer, Andrew Purdy, Harold Sawyer, Richard Sprague, Robert Tannenbaum.
New Orleans DA & Other Authorities: James Alcock, Bernard Bagert, Matthew Braniff, Nicholas Chetta, Jim Garrison, Pershing Gervais, William Gurvich, Aloysius Habighorst, Edward Haggerty, Louis Ivon, Herman Kohlman, Francis Martello, Malcolm O'Hara, Alvin Oser, Andrew Sciambra, William Wood.
Other Government Officials: Clifton Carter, Chester Clifton, John Connally, Douglas Dillon, Don Edwards, Sarah Hughes, Richard Nixon, Lawrence O'Brien, Otto Otepka, Nelson Rockefeller, Walter Sheridan, Adlai Stevenson, Homer Thornberry, Ralph Yarborough.
Officials of Other Governments: Eusebio Azcue, Fidel Castro, Nikita Khrushchev, Valery Kostikov, Oleg Nechiporenko, Yuri Nosenko, Paul Yatskov.