- Harrison Ford as Henry "Indiana" Jones, Jr.: An archaeologist, professor and adventurer who seeks to rescue his father and find the Holy Grail. Ford said he loved the idea of introducing Indiana's father because it allowed him to explore another side to Indiana's personality: "These are men who have never made any accommodation to each other. Indy behaves differently in his father's presence. Who else would dare call Indy 'junior'?"[4]
- River Phoenix as a younger Indiana Jones. Phoenix had portrayed the son of Ford's character in The Mosquito Coast (1986). Ford recommended Phoenix for the part; he said that of the young actors working at the time, Phoenix looked the most like him when he was around that age.[5]
- Sean Connery as Henry Jones, Sr.: Indiana's father, a professor of Medieval literature who cared more about looking for the Grail than raising his son. Spielberg had Connery in mind when he suggested introducing Indiana's father, though he did not tell Lucas at first. Consequently, Lucas wrote the role as "a crazy, eccentric" professor resembling Laurence Olivier, whose relationship with Indiana is "strict schoolmaster and student rather than a father and son".[6] Spielberg had been a fan of Connery's work as James Bond and felt that no one else could perform the role as well.[7] Spielberg biographer Joseph McBride wrote, "Connery was already the father of Indiana Jones since the series had sprung from the desire of Lucas and Spielberg to rival (and outdo) Connery's James Bond films."[8] Gregory Peck was also considered for the role.[5] Connery, who had eschewed major franchise films since his work on the James Bond series, as he found those roles dull and wanted to avoid paparazzi attention, initially turned the role down (as he was only twelve years older than Ford) but eventually relented. Connery—a student of history—began to reshape the character, and revisions were made to the script to address his concerns. "I wanted to play Henry Jones as a kind of Richard Francis Burton," Connery commented. "I was bound to have fun with the role of a gruff, Victorian Scottish father."[7] Connery believed Henry should be a match for his son, telling Spielberg that "whatever Indy'd done my character has done and my character has done it better".[5] Connery signed to the film on March 25, 1988.[6] He improvised the line, "She talks in her sleep", which was left in because it made everyone laugh;[9] in Boam's scripts, Henry telling Indiana that he slept with Elsa occurs later.[6]
- Alex Hyde-White plays Henry in the film's prologue, though his face is never shown and his lines were dubbed by Connery.
- Denholm Elliott as Marcus Brody: Indiana's bumbling English colleague. Elliott returned after Spielberg sought to recapture the tone of Raiders of the Lost Ark (1981), following the actor's absence in the darker Temple of Doom (1984).[5]
- Alison Doody as Dr. Elsa Schneider: An Austrian art professor and Indy's love interest, who is in league with the Nazis. She seduces the Joneses to trick them but seems to be in love with Indy. While the character of Elsa is in her 30s during the film, Doody was 21 when she auditioned and was one of the first actresses who met for the part.[6] Amanda Redman was offered the role, but declined.[10]
- John Rhys-Davies as Sallah: A friend of Indiana and a professional excavator living in Cairo. Like Elliott's, Rhys-Davies's return was an attempt to recapture the spirit of Raiders of the Lost Ark.[5]
- Julian Glover as Walter Donovan: An American businessman who sends the Joneses on their quest for the Holy Grail out of a desire for immortality while secretly working with the Nazis for the same goal. Glover previously appeared as General Veers in Lucas's The Empire Strikes Back. He originally auditioned for the role of Vogel. Glover, who is English, adopted an American accent for the film,[11] but was dissatisfied with the result.[5]
Additionally, Michael Byrne portrays Ernst Vogel, a brutal SS colonel. Byrne and Ford had previously starred in Force 10 from Navarone (1978), in which they also respectively played a German and an American.[12] Kevork Malikyan portrays Kazim, the leader of the Brotherhood of the Cruciform Sword, an organization that protects the Holy Grail. Malikyan had impressed Spielberg with his performance in Midnight Express (1978) and would have auditioned for the role of Sallah in Raiders of the Lost Ark had a traffic jam not delayed his meeting with the director.[12] Robert Eddison appears as the Grail Knight, the guardian of the Grail who drank from the cup of Christ during the Crusades. Eddison was a stage and television veteran only appearing in a few films since the 1930s (including a supporting role in Peter Ustinov's 1948 comedy Vice Versa). Glover recalled Eddison was excited and nervous for his return to film, often asking if he had performed correctly.[13] Laurence Olivier was originally considered to play the Grail Knight,[14] but he was too ill and died the same year in which the film was released.
Michael Sheard appears as Adolf Hitler, whom Jones briefly encounters at the book-burning rally in Berlin. Although a non-speaking role, Sheard could speak German and had already portrayed Hitler three times during his career. He had also appeared as Admiral Ozzel in The Empire Strikes Back and as Oskar Schomburg in Raiders of the Lost Ark. In the same scene, Ronald Lacey, who played Toht in Raiders of the Lost Ark, cameos as Heinrich Himmler. Alexei Sayle played the sultan of Hatay. Paul Maxwell portrayed "the man with the Panama Hat" who took possession of the Cross of Coronado. Wrestler and stuntman Pat Roach, who played three roles in the previous two films, made a short cameo as the Nazi who accompanies Vogel to the Zeppelin. Roach was set to film a fight with Ford, but it was cut. In a deleted scene, Roach's agent boards the second biplane on the Zeppelin with a World War I flying ace (played by Frederick Jaeger), only for the pair to fall to their deaths after the flying ace makes an error. Richard Young played Garth, the leader of the tomb robbers who chased young Indiana Jones and then gives him his hat. Eugene Lipinski portrayed the mysterious agent G-Man, while Vernon Dobtcheff appeared as the butler of Castle Brunwald.
