William J. Genego, a prominent trial and appellate attorney who successfully fought to overturn the wrongful murder convictions of at least five people serving life sentences, has died. He was 66.

Genego died of cancer in his Santa Monica home on Wednesday, said Vicki Podberesky, a friend and former law partner.

“He liked to represent the underdog and righting a wrong,” said Podberesky, who met Genego when she was a student at USC Gould School of Law, where he was a professor. “His enthusiam, passion and compassion for people was inspiring.”

Colleagues said Genego was drawn to cases in which he felt the criminal justice system failed to treat a defendant fairly. He won acquittals in cases involving federal fraud prosecutions and first-degree murder. He also had a reputation for securing appellate reversals in cases including bank fraud, conspiracy, controlled substances and entrapment.

Genego helped overturn the conviction of Marine Cpl. Thomas R. Merrill, who was implicated in a double murder during a coin shop robbery. He also represented Harold Hall, a man convicted of a double slaying in Los Angeles, and had the case overturned and the charges dropped.

One of his most notable cases was in the wrongful conviction of Bruce Lisker, a man who spent 26 years behind bars in the killing of his mother. That case was the subject of a Times investigation that exposed police misconduct and undermined key prosecution evidence.

“He was a soldier,” a tearful Lisker said Thursday. “He had an amazing command of the legal process. Court was not a fun place for me. In the courtroom he was my rock. He was a pillar of strength. He had a glint in his eye that gave me confidence. He took the injustices inflicted on others as a personal affront.”

Genego was born and raised in East Greenbush, New York, near Albany. He went to New York University and drove a cab as an undergrad to pay for his schooling. He graduated from Yale Law School, where he was an editor of the Yale Law Journal. He taught at USC for nine years and went into private practice.

Attorney Evan Jenness, a friend and colleague, said Genego had stacks of letters on his desk from inmates asking for his help. He took the time, she said, to answer them all, assessing their cases. His beloved Jack Russell terrier, Myla, would be by his side.

“He had an indefatigable passion for justice for the disenfranchised,” Jenness said. “He wanted to be there for people who had nobody.”

U.S. 9th Circuit Court of Appeals Judge Stephen Reinhardt said Genego was “a model of what a lawyer should be: a really good person.

“It was clear in cases he argued before me that he had a dedication to the people who were in need of help,” he said. Judith Resnik, a longtime friend and professor at Yale Law School, gave Genego the ultimate endorsement.

“The rule in my household was if you ever got arrested, you call Bill Genego,” she said. “He was a mixture of tireless worker, committed and kind. And when the law failed, he would keep pressing for the law to make good on its promises of justice.”

When Genego became ill, Podberesky helped out with his legal caseload and discovered that he was representing most of his clients for free.

“He did it because he believed these people were wronged,” she said. “He did it because he loved it.”

He is survived by a sister and a brother, Barbara and John Genego; his step children, Nicolo, Lorenzo and Leonardo Nourafchan; their mother, Veronica Gentilli; and grandchildren Zehava, Adelle and Yisroel.

A funeral will be held 9 a.m. Friday at Woodlawn Cemetery in Santa Monica.

In lieu of flowers, the family asks that donations be sent to the ACLU of Southern California designated for “The Bill Genego fund against governmental encroachment on civil liberties.”