Edgar became head of PSU when she lost the use of her legs after receiving a back injury when wounded in the line of duty. She moved around using a hoverchair (anti-gravity wheelchair), and became renowned for her strict discipline and high expectations of her staff. She became PSU's longest serving head, serving twenty-two years. She occasionally used the wealth of confidential information at her disposal to play power games with other judges to increase her own influence. This led people to compare her to the 20th century FBI director J. Edgar Hoover, and she acquired the nickname "J. Edgar Hover" (only ever used behind her back).
In 2117 she was discovered to be illicitly keeping sensitive information on other senior judges, which had been compiled by Judge Cal for the purposes of blackmail when he was head of the SJS, the Judges' internal affairs division. Chief Judge Volt decided to take no action against her, but when Judge Hershey succeeded him as chief judge in 2122, Hershey immediately had Edgar arrested and investigated by the SJS. On trial before the Council of Five, Edgar defended herself with skill and defiance. She briskly and brusquely discredited what had initially seemed to be overwhelming evidence, reducing the prosecution case to nothing more than empty innuendo, and claimed that the charge was politically-motivated.
Besides the seniority of the defendant, Edgar's trial is also notable for being the only occasion when Judge Dredd ever sat on the Council – having always declined a permanent seat – when he agreed to sit in a vacant seat to make up the numbers for the duration of the trial.
Although Edgar was acquitted of all criminal charges, she was still dismissed from office by Chief Judge Hershey. Judge Niles, who was head of SJS and who had personally led the investigation (and brought the whole affair to Hershey's attention in the first place), was transferred from SJS to take over command of the PSU. Edgar was demoted to the lowly position of commanding Cursed Earth Correctional Facility 17, where she remained for eight years.
During the "Chief Judge's Man" story arc she was astonished to be asked to help Dredd catch a killer, a there was clearly too much bad blood for the two to ever reconcile. While head of PSU she forced Dredd's friend Galen DeMarco out of the Justice Department, as well as numerous other run-ins with Dredd.
In the 2008 story "The Edgar Case" she was shown to be in very ill health and on the verge of death from cancer. She finally passed away in prog 1595. By this time Dredd had discovered, too late to arrest her, that she was responsible for seventeen vigilante murders committed over thirty years earlier. This evidence came to light when Edgar, on her death-bed, sent Dredd to investigate the murders, hoping that he might be killed when one of her former accomplices resisted arrest.