The film is based on the true story of Betty Anne Waters, a single mother who works tirelessly to free her wrongfully convicted brother, Kenny. The story unfolds in flashbacks, and the film opens with the scene of the brutal 1980 murder of Katharina Brow in Ayer, Massachusetts. In many ways, Betty Anne's life revolves around her brother, who is now in jail for the murder. Despite Kenny's knack for getting in trouble, they have always been close. After the murder, Kenny is initially brought in for questioning by Sergeant Nancy Taylor (Melissa Leo), but released. Two years later, based on new testimony from two witnesses, Kenny is arrested and tried. The evidence presented at Kenny's trial is entirely circumstantial, but he is convicted of first degree murder and sentenced to life in prison without parole. The three main witnesses against him are Sergeant Taylor, his ex-wife Brenda (Clea DuVall), and ex-girlfriend Roseanna (Juliette Lewis).
Three years later, Betty Anne lives with her husband, Rick (Loren Dean) and two sons, Richard and Ben. She is frantic that she has not heard from Kenny, who calls her every week from prison, and finally discovers that he tried to commit suicide. Betty Anne decides to go back to school and become a lawyer so she can exonerate him, but her husband is skeptical and unsupportive, and eventually they split up. As Betty Anne struggles with being a working mother attending law school, flashbacks reveal that her mother was callous and uncaring, forcing Kenny and Betty Anne to fend for themselves. The two were very close, but frequently got into trouble, and were eventually taken away from their mother and sent to separate foster homes.
Betty Anne continues to visit Kenny in prison, working in a bar while going to school, but her busy schedule causes her to miss a planned outing with her sons, who decide they would be better off living with their father. Struggling in school, demoralized and exhausted, Betty Anne stops going to classes, until a friend from school, Abra (Minnie Driver), comes to her house and prods her to just get up, get dressed, and get back to class.
In a study group, Betty Anne learns about the new field of DNA testing and realizes that this could be the key to overturning Kenny's conviction, as only blood types had been matched at the time of the trial. She contacts attorney Barry Scheck from the Innocence Project. The backlog of cases will mean waiting at least 18 months unless she can pass the Bar exam and find the blood evidence from Kenny's trial herself to have it tested. She officially passed the Bar Exam and now a full-time lawyer. She begins working on Kenny case. At first she is stonewalled, then told the evidence was destroyed, but she refuses to give up, and she and Abra embark on an odyssey to recover any evidence that might still be stored away somewhere. In the process, Betty Anne learns that Nancy Taylor was fired from the police department for fabricating evidence in another case, which deepens Betty Anne's suspicions about Kenny's conviction and the evidence presented at trial. Finally the DNA results come back and establish that the blood was not Kenny's. Betty Anne and Kenny are overjoyed anticipating his release, but Martha Coakley, of the District Attorney's office, refuses to vacate the conviction, claiming that there was still enough evidence to convict Kenny as an accomplice. Kenny is convinced that no matter what, the authorities will find a way to keep him in prison to avoid admitting their mistake. Betty Anne is heartbroken again, but refuses to give up after Barry advises her that their discovery not only proves Kenny's innocence, but also that the main witnesses against him were lying.
Betty Anne, Abra, and Barry Scheck visit the other two main trial witnesses, Kenny's ex-wife and his ex-girlfriend. Both tearfully confess that Sergeant Nancy Taylor coerced and threatened them into perjuring themselves at Kenny's trial. With an affidavit from Kenny's ex-wife and the DNA evidence, Kenny's conviction is vacated and he is freed from prison after 18 years in June 2001. Betty Anne is able to persuade his daughter, Mandy (Ari Graynor), whom he hadn't had any contact with since she was a small child, that he never stopped trying to reach out to her while he was in prison despite his ex-wife's efforts to estrange them. He is able to reconnect with his daughter, and is reunited with his sister and her sons.
The epilogue states that Betty Anne secured a large civil settlement from the City of Ayer's Police Department for Kenny's wrongful conviction eight years later, but former Sergeant Nancy Taylor (whom Betty Anne also won the settlement against) was immune from prosecution because the Massachusetts statute of limitations had expired. Betty Anne continues to work at the pub and is still a part of the Innocence Project, helping to prevent other wrongful convictions, while the real murderer of Katharina Brow has never been found.Hilary Swank - Betty Anne Waters
Bailee Madison - Young Betty Anne Waters
Sam Rockwell - Kenny Waters
Minnie Driver - Abra Rice
Ele Bardha - Don
Melissa Leo - Nancy Taylor
Ari Graynor - Mandy Marsh
Loren Dean - Rick Miller
Karen Young - Elizabeth Waters
Jennifer G. Roberts - Martha Coakley
Clea DuVall - Brenda Marsh
Juliette Lewis - Roseanna Perry
Peter Gallagher - Barry Scheck
Conor Donovan - Richard Miller
Owen Campbell - Ben Miller
J David Moeller - Ben Davenport
Dr. Azrael Paredes - Intern
Jordan Moratsuchi - Law Student
Eric McCoy - Wiley
Michele Messmer - Katharina Brow
Production began in February 2009, in Dexter, Michigan. Filming also took place in Ann Arbor, Howell, Pinckney, Chelsea and Ypsilanti. In Ypsilanti, filming took place in the historic Depot Town at a restaurant called Sidetrack Bar & Grill. In Howell, filming took place at the Livingston County Courthouse, along Dearborn Street at Cole's Elevator, and at the Howell Village Market (formerly Sefa's Super Market). The script was written by Pamela Gray. The poster was released June 21, 2010.
The film score was composed by composer Paul Cantelon.
The end title song is "Heaven & Hell" by Cantelon's band, Wild Colonials. The song is a re-recording of the track that first appeared on their debut album, Fruit of Life and was released as a stand-alone single at the time of the film's release.
Review aggregate Rotten Tomatoes reports that 67% of critics have given the film a positive review based on 179 reviews, with an average score of 6.2/10. The critical consensus reads "Less compelling – and more manipulative – than it should be, Conviction benefits from its compelling true story and a pair of solid performances from Swank and Rockwell." Another review aggregator Metacritic assigned the film a weighted average score of 61 out of 100, indicating "generally positive reviews".
Martha Coakley, Attorney General of the Commonwealth of Massachusetts, who was portrayed in the film, commented after seeing a pre-screening on October 12, 2010, that it was a compelling film but there were legal inaccuracies or temporal exaggerations. Family members of Katharina Brow, the murder victim, have criticized the film company and Hilary Swank for failing to consult the family on the movie's depiction of their mother. Betty Anne Waters stated that the Brow family did not try to make any contact with her or Kenneth Waters when he was exonerated, nor did they offer any condolences when he died. Kenneth died in September 2001, six months after his exoneration, due to a head injury he sustained in an accident.