US President George Bush has reaffirmed his support for the death penalty, following the 1,000th execution since it was reintroduced in 1976.
Boyd was the 1,000th person to be put to death in the US since 1976
Killer Kenneth Boyd was put to death in North Carolina on Friday.
White House spokesman Scott McClellan said Mr Bush "strongly supports" the death penalty because "ultimately it helps save innocent lives".
Although a majority of Americans back the death penalty, polls show that public support is decreasing.
Texas accounts for 355 of the 1,000 executions carried out since a 10-year ban on capital punishment was overturned by the US Supreme Court in 1976.
During his six years in office as governor of Texas, Mr Bush commuted one death sentence and allowed 152 to go ahead.
Speaking to reporters in Washington, Mr McClellan said: "When it's administered fairly and swiftly and surely, it serves as a deterrent."
He added that Mr Bush had promoted an initiative to expand the use of DNA evidence to help prevent wrongful convictions.
US EXECUTIONS SINCE 1976
Texas - 355
Virginia - 94
Oklahoma - 79
Missouri - 66
Florida - 60
Georgia - 39
North Carolina - 38
South Carolina, Alabama - 34 each
Louisiana, Arkansas - 27 each
Arizona - 22
Ohio - 19
Indiana - 16
Delaware - 14
Illinois - 12
Nevada, California - 11 each
Mississippi, Utah - 6 each
Maryland, Washington - 4 each
Nebraska, Pennsylvania - 3 each
Kentucky, Montana, Oregon - 2 each
Colorado, Connecticut, Idaho, New Mexico, Tennessee, Wyoming - 1 each
US government - 3
Source: US Death Penalty Information Center
Hours earlier, Boyd had been executed by lethal injection.
He spent 11 years on death row after being convicted of shooting his estranged wife and her father in 1988.
He spent his last hours with visiting friends and family, including one of his sons, 35-year-old Kenneth Smith, and his wife Kathy and two children.
"This 1,000th execution is a milestone. It's a milestone we should all be ashamed of," Boyd's lawyer Thomas Maher said after watching him die.
A group of about 150 death penalty opponents had gathered outside the Central Prison in Raleigh, North Carolina, where the execution took place.
Amnesty International's Kate Allen said that the landmark death "puts the US in the same company as countries like China, Iran, Saudi Arabia and Vietnam".
A Gallup poll in October showed 64% of Americans support the death penalty, the lowest level in 27 years and down from a high of 80% in 1994.
The BBC's Justin Webb in Washington says that in recent years, enthusiasm for the punishment has dwindled in the US and the courts have been less inclined to use it.
Later on Friday, the US saw its 1,001st execution when Shawn Humphries died by lethal injection in South Carolina.
He had received the death penalty for the 1994 murder of a shopkeeper.
His lawyer said Humphries would have preferred to be the 1,000th person to be executed, so that his death could be a milestone.
US SUPPORT FOR DEATH PENALTY
Question asked: Are you in favour of the death penalty for a person convicted of murder?
All samples 800-1,000 adults
Face-to-face and telephone interviews
Margin for error +/- 3%