Guinness's role as Obi-Wan Kenobi in the original Star Wars trilogy, beginning in 1977 with Star Wars, brought him worldwide recognition to a new generation, as well as Academy Award and Golden Globe nominations. In letters to his friends, Guinness described the film as "fairy-tale rubbish" but the film's sense of moral good – and the studio's doubling of his initial salary offer – appealed to him and he agreed to take the part of Kenobi on the condition that he would not have to do any publicity to promote the film.[39]

He initially negotiated a deal for 2% of the film's royalties paid to the director, George Lucas, who, upon the warm reception of the film with the press and film critics, and as a gesture of good-will for the positive amendments and suggestions Guinness proposed to the screenplay for the film, offered Guinness an additional 0.5%, bringing his share to 2.5%. When Guinness enquired about the share with the film's producer Gary Kurtz, and asked for a written agreement so as to codify his earnings, Kurtz revised Lucas's offering down by 0.25%, bringing Guinness's final, agreed-upon share of royalties paid to the director to 2.25% (Lucas received one-fifth of the overall box office takings, which would take Guinness's share of the overall box office to 1.80%).[40][41]

Upon his first viewing of the film, Guinness wrote in his diary, "It's a pretty staggering film as spectacle and technically brilliant. Exciting, very noisy, and warm-hearted. The battle scenes at the end go on for five minutes too long, I feel, and some of the dialogue is excruciating and much of it is lost in noise, but it remains a vivid experience."[42]

Guinness soon became unhappy with being identified with the part and expressed dismay at the fan following that the Star Wars trilogy attracted. In the DVD commentary of the original Star Wars, Lucas says that Guinness was not happy with the script rewrite in which Obi-Wan is killed. Guinness said in a 1999 interview that it was actually his idea to kill off Obi-Wan, persuading Lucas that it would make him a stronger character and that Lucas agreed to the idea. Guinness stated in the interview, "What I didn't tell Lucas was that I just couldn't go on speaking those bloody awful, banal lines. I'd had enough of the mumbo jumbo." He went on to say that he "shrivelled up" every time Star Wars was mentioned to him.[43]