During his tenure with the center, which began in 1975 and continued the medical practice of his father, Tiller was frequently targeted with protest and violence by anti-abortion groups and individuals. After his clinic was firebombed in 1986, Tiller was shot in both arms by anti-abortion extremist Shelley Shannon in 1993. On May 31, 2009, Tiller was fatally shot in the side of the head by anti-abortion extremist Scott Roeder, as Tiller served as an usher during the Sunday morning service at his church in Wichita. Roeder was convicted of murder on January 29, 2010, and sentenced to life imprisonment.
Tiller was born in Wichita, Kansas, the son of Catherine and Dean Jackson "Jack" Tiller, MD. He studied at the University of Kansas School of Medicine from 1963 to 1967. Shortly thereafter, he held a medical internship with United States Navy, and served as flight surgeon in Camp Pendleton, California, in 1969 and 1970. In July 1970, he planned to start a dermatology residency. However, on August 21, 1970, his parents, sister and brother-in-law were killed in an aircraft accident. In her will, his sister requested that Tiller take care of her one-year-old son. Tiller had intended to go back to Wichita, close up his father's family practice and then go back to become a dermatologist. However, he quickly felt pressure to take over his father's family practice. Tiller's father had performed abortions at his practice. After hearing about a woman who had died from an illegal abortion, Tiller stayed in Wichita to continue his father's practice.
At the time of his death, Dr. Tiller was board certified with the American Board of Family Practice, an Associate of the American Society of Addiction Medicine, and a clinical instructor in the Department of Family Medicine for Wesley Medical Center, where he had previously served as president of the medical staff.
Tiller's practice performed late-term abortions, which made Tiller a focal point for anti-abortion protest and violence. Tiller treated patients who discovered late in pregnancy that their fetuses had severe or fatal birth defects. He also aborted healthy late-term fetuses in cases where two doctors certified that carrying the fetus to term would cause the woman "substantial and irreversible impairment of a major bodily function". His practice frequently made him the focus of anti-abortion groups. The Kansas Coalition for Life kept a daily vigil outside Tiller's facility from May 9, 2004, until May 31, 2009. The group known as Operation Rescue held an event called 'The Summer of Mercy' in July and August 1991, focusing on Tiller's clinic but also protesting other abortion providers in Wichita, Kansas. Years later, a branch that split from the main Operation Rescue group moved from California to Kansas specifically to focus on Tiller, initially named Operation Rescue West.
Kansas law prohibits abortions after the beginning of fetal viability unless two doctors certify that continuing the pregnancy would cause the woman "substantial and irreversible impairment of a major bodily function". The two consulting doctors must not be "financially affiliated" with the doctor doing the abortion. Tiller was charged with 19 misdemeanors for allegedly consulting a second physician in late-term abortion cases during 2003 who was not truly "unaffiliated". The case became a cause célèbre for both supporters and opponents of legal abortion. WorldNet Daily Columnist Jack Cashill compared the trial to the Nuremberg Trials of Nazi war criminals, while Icahn School of Medicine at Mount Sinai Professor Jacob Appel described Tiller as "a genuine hero who ranks alongside Susan B. Anthony and Martin Luther King Jr. in the pantheon of defenders of human liberty". The trial took place in March 2009, with the jury finding Tiller not guilty on all charges on March 27, approximately two months before his death.
Dr. Tiller struggled with substance abuse, which came to a head in 1984 when he was arrested for driving under the influence. He sought treatment, overcame his difficulties, and later served on the Kansas Medical Society’s impaired physicians committee.
Tiller was discussed in 28 episodes of the Fox News talk show The O'Reilly Factor before his death in May 2009, focusing national attention on his practice. Although he later denied it, show host Bill O'Reilly sometimes described him as "Tiller the Baby Killer", a nickname that Congressman Robert Dornan had used on the floor of the US House of Representatives. O'Reilly said he would not want to be Tiller, Kathleen Sebelius, and other pro-choice Kansas politicians "if there is a judgment day". On November 3, 2006, O'Reilly featured an exclusive segment on The O'Reilly Factor, saying that he had an "inside source" with official clinic documentation indicating that Tiller performed late-term abortions to alleviate "temporary depression" in pregnant women. He characterized the doctor as "a savage on the loose, killing babies willy-nilly", and accused him of "operating a death mill", and of protecting the rapists of children. He suggested that Tiller performed abortions for women who had "a bit of a headache or anxiety" or who felt "a bit blue".
After Dr. Tiller was murdered, O'Reilly denied responsibility and defended his campaign against Dr. Tiller, saying: "When I heard about Tiller’s murder, I knew pro-abortion zealots and Fox News haters would attempt to blame us for the crime, and that’s exactly what has happened. [...] Every single thing we said about Tiller was true, and my analysis was based on those facts. [...] Now, it’s clear that the far left is exploiting—exploiting—the death of the doctor. Those vicious individuals want to stifle any criticism of people like Tiller. That—and hating Fox News—is the real agenda here."
Throughout his career, Tiller was a frequent target of anti-abortion violence. In June 1986, his clinic was firebombed. While it was being rebuilt, Tiller displayed a sign reading "Hell no, we won't go". On August 19, 1993, Shelley Shannon shot Tiller five times, while he was in his car. At the time she attacked Tiller, Shannon had been an anti-abortion activist for five years and had written letters of support to the convicted murderer Michael Griffin, who had murdered Dr. David Gunn. She called him "a hero". At her trial in state court, Shannon testified that there was nothing wrong with trying to kill Tiller. The jury convicted Shannon of attempted murder, and she was sentenced to 11 years in prison. The following year, however, Shannon was sentenced to an additional 20 years in prison on charges of arson, interference with commerce by force and interstate travel in aid of racketeering in connection to her participation in several fires and acid attacks on abortion clinics.
Tiller was fatally shot in the side of the head on May 31, 2009, by anti-abortion extremist Scott Roeder during worship services at the Reformation Lutheran Church in Wichita, where he was serving as an usher and handing out church bulletins. After threatening to shoot two people who initially pursued him, Roeder fled and escaped in a car. Three hours after the shooting, Roeder was arrested about 170 miles (270 km) away in suburban Kansas City. On June 2, 2009, Roeder was charged with first-degree murder and two counts of aggravated assault in connection with the shooting, subsequently convicted in January 2010 on those charges, and sentenced on April 1, 2010, to life imprisonment without parole for 50 years, the maximum sentence available in Kansas.
Tiller's killing was largely condemned by groups and individuals on both sides of the abortion issue. US President Barack Obama said he was "shocked and outraged" by the murder. David N. O'Steen, director of the National Right to Life Committee, said the group "unequivocally condemns any such acts of violence regardless of motivation". Some others who spoke publicly were more confrontational. Anti-abortion activist Randall Terry described Tiller as a mass murderer and said of other abortion providers, "We must continue to expose them in our communities and peacefully protest them at their offices and homes, and yes, even their churches", and Southern Baptist minister and radio host Wiley Drake said, "I am glad that he is dead".
After the shooting, Tiller's colleague, Leroy Carhart of Nebraska, stated that Tiller's clinic, Women's Health Care Services, would reopen after being closed for one week to mourn his death. The following week, Tiller's family announced that the clinic would be closed permanently.
The aftermath of Tiller's assassination was the subject of the 2013 documentary After Tiller, which followed the daily lives and work of the four remaining late-term abortion providers in the United States.
The George Tiller Memorial Abortion Fund was established by the National Network of Abortion Funds.
Trust Women Foundation purchased and re-opened the clinic that Dr. George Tiller operated and currently operates as the Southwind Women's Center performing abortions and other medical services. The foundation currently operates two clinics; one in Wichita, KS and one in Oklahoma City, OK.