On January 20, 1997, Elvis Presley's former manager, Colonel Tom Parker, is on his deathbed, having suffered a stroke. Nursing a gambling addiction that has left him destitute, he recounts how he first met the future King of Rock and Roll.

Raised mostly by his doting mother Gladys, Presley spends his childhood in the poorest parts of Mississippi, finding an escape in the comic book adventures of Captain Marvel Jr. and especially in song. However, upon moving with his parents to Memphis, he is ridiculed by his peers due to his fascination with the African-American music of Memphis's Beale Street. At this time, Parker is a carnival "huckster" who fancies himself a modern-day P. T. Barnum. Although partnered with country singer Hank Snow, Parker immediately realizes Presley's crossover potential when he hears the white artist "sounding black" on the groundbreaking single, "That's All Right." That night, he sees Presley at a "Louisiana Hayride" performance, discovering a talented musician with strong sex appeal.

At a Ferris Wheel, Parker meets with Presley and persuades him to let him take exclusive control of his career, beginning a meteoric ascent that sees the Presley family lifted out of poverty. The regional public is divided in their view of the singer. Feeling that Presley's music will corrupt white children and stoke racial hostility, segregationist Southern Democrat Mississippi Senator James Eastland calls Parker to an informal hearing, during which he questions Parker about his mysterious past.

After Presley's charged dance moves at a concert, the singer faces potential legal trouble. Parker persuades the government to draft Presley into the US Army instead to avoid legal entanglements. During his military service in West Germany, Presley is devastated by his mother's alcoholism-induced death. Presley finds some solace when he meets Priscilla Beaulieu, the adopted teenage daughter of an United States Air Force pilot. After his discharge, he resumes his movie career, and years later, he marries Priscilla.

As the popular culture of the 1960s passes Presley by, the assassinations of Martin Luther King Jr. and Robert F. Kennedy devastate him. Although he wants to become more politically outspoken in his music, Parker only allows him to release frivolous feel-good songs. Presley eventually decides to revamp his image by developing his own entourage, the "Memphis Mafia", which includes Priscilla, his friend Jerry Schilling, and several others. Ultimately, he redirects a corporate-sponsored Christmas special television shoot into a career revival based on a return to older songs and a direct acknowledgment of his use of sexuality in performance via an all black-leather performance outfit. His performance choices in the special, including the closing number, "If I Can Dream", are presented and perceived as acts of political commentary. Infuriated corporate sponsors threaten litigation, while a disgusted Parker believes Presley has been "brainwashed by hippies." Nevertheless, the show is massively successful.

After the special, Presley headlines at the largest showroom in Las Vegas, the International Hotel, and then resumes concert tours. Parker's control of Presley's life tightens further as he refuses Presley's request for a world tour despite initially promising him and tricks him into signing a contract for a lengthy Las Vegas casino residency. Presley's behavioral issues and prescription drug addiction overtake him, and a despondent P