Scott Roeder argued that he had chosen to obey "God's law" to save babies.
"I stopped him so he could not dismember another innocent baby," Roeder said. "Wichita is a far safer place for unborn babies without George Tiller."
Roeder was sentenced Thursday to life in prison with no possibility of parole for 50 years, the longest sentence possible under Kansas law for first-degree murder.
The 52-year-old Kansas City, Missouri, man killed Tiller as Tiller was serving as an usher last May in the foyer of the doctor's church in Wichita.
Roeder also was sentenced to an additional year in prison on each of two counts of aggravated assault for threatening two church ushers as he fled. With time off for good behaviour, Roeder won't be eligible for parole for 51 years and eight months.
An attorney for Tiller, speaking in court as a friend of the slain doctor, said the toughest sentence would discourage other anti-abortion zealots from attacking doctors. Tiller's widow, Jeanne, cried as the sentence for murder was announced.
"We only can hope that this sentence will serve as a deterrent to those who have conspired and continue to conspire to murder abortion providers," the Tiller family said in a statement. "Certainly everything possible should be done by the prison system to insure that this man does not continue to foment hatred and violence from his prison cell."
MORE ON CRIMESIDER
December 22, 2009 - Scott Roeder's Defense: I Killed Abortion Doctor George Tiller to Protect "Preborn Children"
November 10, 2009 - Roeder Admits Killing Kansas Abortion Doctor George Tiller; Says He Has No Regrets
October 26, 2009 - What Will EBay Do? Anti-Abortion Auction Slated for Alleged Killer of Abortion Doctor George Tiller
June 11, 2009 - Abortion Foes Want To Buy Slain Abortion Doc's Clinic
June 8, 2009 - Alleged Abortion Doc Killer Says More Murders Planned
June 4, 2009 - PETA Places Billboards In Wake Of Tiller Murder
June 2, 2009 - Man Charged With Killing Abortion Doc Has Long Anti-Gov History
June 2, 2009 - Abortion Debate Rages: Tiller Called "Mass Murderer"
June 2, 2009 - Abortion Foes Fear Backlash To Tiller's Slaying
June 1, 2009 - Abortion Doctor Murdered In Church, Suspect Jailed