Gosnell was also sentenced to 2 ½ to five years in prison for the 2009 overdose death of a patient. The sentences are consecutive, meaning Gosnell, 72, will spend the rest of his life in prison.
The case has made Gosnell a flashpoint in the nation's bitter debate over legalized abortion.
Prosecutors argued that Gosnell savagely killed late-term babies born alive by severing their spines, and taught several staff members the technique. Nine former clinic workers were convicted in the case, and four others pleaded guilty to murder.
Despite the notoriety of the case, Gosnell has seemed oddly serene in court during the two-month trial, and apparently sees himself as a medical pioneer and tireless advocate for inner-city patients.
"I wanted to be an effective, positive force in the minority community," Gosnell told The Philadelphia Daily News in a 2010 interview, when he predicted he would be "vindicated" of the allegations in a harrowing grand jury report. He chose not to address the judge during Wednesday's sentencing.
But prosecutors said he grew increasingly reckless as he accumulated millions of dollars from his rogue clinic, which was described as a "pill mill" for addicts by day and an "abortion mill" by night.
The jury spent 10 days deliberating before finding that Gosnell had killed babies or had them killed. And the jury found him complicit in the death of the 41-year-old patient, a Virginia woman who was repeatedly sedated by his untrained medical assistants.
Gosnell was also convicted of hundreds of abortion law violations for performing illegal, third-term abortions or failing to counsel women and teens. Gosnell was acquitted in the deaths of four other infants.
Prosecutors have declined to comment on the verdict, citing a gag order that was expected to be lifted Wednesday when Gosnell's sentence is finalized.
Prosecutors had planned to seek the death penalty because Gosnell killed more than one person and his victims were especially vulnerable given their age. But Gosnell's own advanced age had made it unlikely he would ever be executed before his appeals ran out.
Gosnell's lawyer, Jack McMahon, said his client accepts the verdict and isn't sorry he went to trial. He said Gosnell gave up a somewhat better deal early on but wanted to air the issues in court and is satisfied that he did so.
"He wanted this case aired out in a courtroom and it got aired out in a courtroom in a fair way. And now he's accepting what will happen. He's an intelligent guy," said McMahon, who said Gosnell would now plead to federal drug charges that are still pending.
The sentencing deal, reached after hours of terse negotiations Tuesday, spares Gosnell's family the task of pleading for his life in court, McMahon said. Gosnell has six children, the youngest of them a teenager born to his third wife, who has also pleaded guilty in the case.
"He's a proud man. To bring his young family into court was something he did not want to do," McMahon said.
A 2011 grand jury investigation into Gosnell's alleged prescription drug trafficking led to the gruesome findings about his abortion clinic. During an FBI raid, authorities found 47 aborted fetuses stored in clinic freezers, jars of tiny severed feet, bloodstained furniture and dirty medical instruments, along with cats roaming the premises.
Prosecution experts said the Delaware teen carrying Baby A, whose death Gosnell was sentenced in Wednesday, was nearly 30 weeks pregnant when Gosnell aborted her fetus. A second baby was said to be alive for about 20 minutes before a clinic worker snipped the neck. A third was born in a toilet and was moving before another clinic employee severed the spinal cord, according to testimony.
A fourth baby let out a whimper before Gosnell cut the neck, prosecutors alleged. Gosnell was acquitted in that baby's death, the only one of the four in which no one testified to seeing the baby killed.
McMahon has argued that none of the fetuses was born alive and that any movements were posthumous twitching or spasms.