A musician helps a young singer find fame as age and alcoholism send his own career into a downward spiral.
Jackson Maine is a talented singer-songwriter with a history of substance abuse known only to those closest to him. One night, he meets Ally, who also writes her own songs but has never been given an outlet to perform. Jack falls for Ally and invites her to join him for one of his shows to sing a song that she wrote, “Shallow”. Although a bit reluctant, Ally quits her job and goes to Jack’s show where they perform the song. It becomes a hit, and Ally has people’s attention.
Ally is signed by record producer Rez Gavron, and her career begins to take off. Meanwhile, Jack supports her while still dealing with his drinking and pill-popping. It gets so bad that he humiliates himself and Ally at the Grammy’s when she wins an award, but he is drunk and he pisses himself. Jack is then put into a rehab program.
As Ally is preparing to go on tour, Rez orders Jack to stay away from Ally because he will just do more harm around her. Ally plans to spend more time with Jack, who says he will go to her last concert after she tells him she will cancel the tour. Jack instead pops more pills that night and commits suicide by hanging himself.
A memorial service is held for Jack where Ally sings a song that he wrote but never got to sing called “I’ll Never Love Again”.
The film starts with popular singer Jackson Maine (Bradley Cooper) getting ready to perform to a sold-out audience, but only after secretly taking a few pills. He sings the song “Black Eyes”, which the crowd loves.
Elsewhere, Ally (Lady Gaga) is a songwriter working at a catering hall. She is seen apparently breaking up with someone over the phone before joining her friend Ramon (Anthony Ramos) at work where she gets constantly chewed out by her boss Bryan (Jacob Schick). After work, Ally heads toward a performance while singing to herself.
After Jack’s show, his driver Phil (Greg Grunberg) brings him to a drag bar. There, he meets Ramon and has some drinks as Ally goes up to perform “La Vie en Rose”. Jack is moved to tears by Ally’s voice, and Ramon arranges for the two of them to meet in the dressing room. Jack charms Ally and invites her to have a drink, but first Jackson performs a song for one of the drag queens there.
Jack takes Ally to a cop bar where she tells him that she doesn’t sing her own songs because people have told her that while they like her music, they don’t like her face. Jack disagrees and tells Ally that she is beautiful. An off-duty cop then walks over and harasses Jack for a photo, which Ally finds disrespectful, and she punches the man in the face. Jack then takes Ally to a grocery store to get frozen peas for her hand. Outside the store, Ally sings the song “Shallow” that she wrote, and Jack loves it.
Jack brings Ally home and invites her to see him perform at a show, but she declines as she has to go to work. Ally returns home to her father Lorenzo (Andrew Dice Clay) and his friends, who all work together as part of a driving service.
Phil later goes to Ally’s home to pick her up to fly her to the show, but Ally insists that she has to work. While at work, Ally gets annoyed when Bryan chastises her for being late, so she finally decides to quit, and she takes Ramon with her to fly and see Jack, who starts by performing one of his hits, “Maybe It’s Time”. At the show, Jack invites a nervous and hesitant Ally onstage to sing “Shallow” together, and the audience loves it. Videos of their performance becomes a viral sensation.
Jack brings Ally back to his hotel room for some alone time. However, Jack gets high and passes out. His manager/older brother Bobby (Sam Elliott) has to help Jack into bed. Bobby tells Ally that he hasn’t seen Jack perform like that in a while, and he credits her for that, but he also warns her to be careful around him.
Ally starts to join Jack as he tours around the country, and they start to form a relationship. One day, Jack tries to bring Ally to a farm that he bought for Bobby, only to find that Bobby sold it. He finds Bobby and punches him in the face, feeling that Bobby betrayed him and their father. Bobby blames their father for introducing Jack to alcohol and he states that his body was washed away in the storm. Bobby then quits working with Jack.
Ally joins Jack for another performance onstage to sing “Always Remember Us This Way”. After the show, Ally meets Rez Gavron (Rafi Gavron), a record producer who wants to sign her to his label. Although he’s not crazy about the idea, Jack supports her and stands behind her.
Ally soon becomes a rising star in music, and she and Jack start to live together with a dog named Charlie. During one of her shows, she chooses to leave her dancers offstage, which doesn’t sit well with Rez. He also suggests that she dye her hair blonde, which Ally doesn’t want to do. She eventually dyes it a bright red color.
Jack tells Ally that he will be at one of her shows, but he actually gets loaded and passes out in front of the home of his old friend, George “Noodles” Stone (Dave Chappelle), a retired musician. Noodles invites Jack inside to share a meal with his wife and kids. Ally later shows up and forgives Jack for missing out on her. He goes into another room and cuts a piece of guitar string to fashion into a ring. With it, he uses it to propose to Ally, and Noodles then suggests that he can arrange for them to be married the same day. With several people in attendance, Jack and Ally tie the knot.
Ally’s career continues to skyrocket, while Jack continues to hide his substance abuse. Rez books Ally a spot as the musical guest on “Saturday Night Live” where Alec Baldwin is hosting. She performs a new song, “Why Did You Do That?” As Jack watches Ally onstage, Bobby shows up, and the two of them reconcile.
While Ally is taking a bath, a very drunk Jack starts to berate Ally for her suggestive new song, making her seem like a whore and calling her ugly. Ally angrily sends Jack out.
Ally gets nominated for three Grammy Awards, including Best New Artist. Jack is hired to play a Roy Orbison tribute with a younger artist. During the performance of “Pretty Woman,” Ally notices that Jack is clearly drunk/high, but he manages to make it through the song. Later, Halsey announces Ally as the Best New Artist winner. Ally goes up to accept and gives a speech, but Jack screws it up by hobbling onstage and then pissing himself right next to Ally, and finally fainting. Lorenzo and his friends bring Jack into the bathroom where he yells at Jack for ruining Ally’s big night. Ally stays by Jack’s side in the shower.
Jack later joins a rehab program and attends AA meetings. When Ally visits him, Jack tearfully apologizes to her for what he’s been doing. Ally later tries to suggest to Rez that Jack join her for her upcoming tour, but he says that’s out of the question, and Ally says she would rather cancel the tour. Rez later personally talks to Jack and tells him that he ought to stay away from Ally because he is just going to drag her down with his behavior and substance use.
Before heading to one of her shows, Ally tells Jack that she is canceling her tour so that they can spend the summer together. Jack promises he will go to her last concert.
Ally is at her show waiting for Jack to show up, but he is at home, having taken some pills. He goes into his garage with his belt and shuts the door with Charlie sitting outside. In between songs, Ally asks someone to go to the house to pick Jack up, but he has already hung himself.
After Jack’s death, Ally is distraught and spends time alone, but she has a breakdown and smashes a couple of framed posters. Bobby consoles her and tells her that Jack’s death was his own fault and not her own. She is remorseful because the last thing she did was lie to him.
A memorial service for Jack is held. Ally performs a song that Jack had written but never sang called “I’ll Never Love Again”. As she sings, there are clips shown of the time the two spent together, ending with Jack singing the end of the song himself for Ally.