Lerner also sentenced Tina Baldwin, 48, a receptionist at Gosnell's Women's Medical Society clinic, 3801 Lancaster Ave., to 30 months' probation for her guilty pleas to sustaining a corrupt organization, conspiracy, and corrupting a minor.
Both women cooperated with prosecutors and testified against Gosnell at his trial last year.
Gosnell, 73, and the others were charged in February 2011 in the clinic's operation, where illegal late-term abortions were performed, and babies born alive and viable were killed.
All but Gosnell pleaded guilty. He was found guilty of murder last year and sentenced to three consecutive life terms in prison.
Both women were typical of those Gosnell hired: poorly educated, with serious personal problems, and willing to work for cash "under the table."
Williams was a widow with three children who met Gosnell at a Wilmington abortion clinic where he also worked. Gosnell began treating her for bipolar illness and hired her.
Baldwin began working for Gosnell after her internship at the clinic when she was at Germantown High School.
Baldwin's lawyer, Colin R. Hueston, asked Lerner for probation, noting that she reports to a federal prison July 7 to begin an 18-month term on her guilty plea to drug conspiracy charges involving the sale of narcotic prescriptions at Gosnell's clinic.
"I wish I never got involved," Baldwin told Lerner. "I'm sorry for the things I did."
Williams' case proved more problematic.
Assistant District Attorney Edward Cameron asked for 10 to 20 years in prison, noting that she killed two people.
One was the 2009 death of an abortion patient to whom Williams gave too much anesthesia. The other was an infant born alive whose spinal cord she snipped with surgical scissors - Gosnell's technique for terminating live births.
"She is an adult, she is a mother herself," Cameron argued. "This was a living human being in front of her, a living human being who was crying."
Defense attorney Stephen P. Patrizio called Cameron's request outrageous in light of Williams' help in prosecuting Gosnell. He said Williams' personal problems made her vulnerable to Gosnell: "This man had a Rasputin-like control over her."
Williams told Lerner she "felt manipulated, used, and lied to by Dr. Gosnell."