BRIDGEPORT — A lion of the state’s legal system roars no more.

Michael P. Koskoff, a longtime Westport resident who, for more than 40 years, defended people’s civil rights and protected residents from medical malpractice, died Wednesday morning with his family at his side. He was 77.

As senior partner of the local law firm Koskoff, Koskoff and Bieder, Koskoff, who died after a long illness, won some of the largest civil verdicts in state history on behalf of clients. But in additional to all his awards and wins in the courtroom, Koskoff will also be remembered for his great compassion and work in the community where he grew up.

Koskoff counted his recent successes as his finest, co-writing with his son, Jacob Koskoff, the screenplay for a critically acclaimed movie about racial-barrier-breaking Supreme Court Justice Thurgood Marshall.

“It is with great sadness that we mourn the passing of a dear friend, colleague and mentor. Michael P. Koskoff spent his entire career working to thwart injustice, stop corporate and governmental abuse, and give a strong voice to the disenfranchised,” said a statement issued from the law firm. “For those of us who were privileged to work with Michael on a daily basis, he was a constant source of inspiration — and creative approaches to complex issues. His dedication, his energy, his optimism, and his courage will be missed by us all.”

Mayor Joe Ganim called Michael Koskoff “a giant among lawyers, and one of the most well-respected legal minds of our time. He was both brilliant and a humanitarian that defended the rights of people. He had a tremendous positive impact as a member of the legal community in the Bridgeport area and beyond.”

State Sen. Richard Blumenthal said he worked with Koskoff for 30 years and considered him a friend.

“Mike Koskoff was a powerhouse civil rights advocate, crusader for justice and a role model for so many of us in the legal profession,” Blumenthal said. “He was fearless and relentless. We will miss his great humor, caring spirit and friendship.”

While Koskoff’s work in the law will always be remembered, early in his career he nearly took a turn at the crossroads, choosing the theater over the law.

Generations of the Koskoff family were in the performing arts. His grandmother had been an actress; his grandfather, a singer; two cousins were composers, and his father, the venerable attorney Theodore Koskoff, had been a professional cellist before starting the Koskoff law firm.

Michael Koskoff studied at the American Shakespeare Academy in Stratford but eventually enrolled in the University of Connecticut School of Law after deciding his future wasn’t in acting.

But it wasn’t until the late spring of 1969 that Koskoff decided he definitely wanted to be a lawyer.

That May, downtown New Haven was taken over as members of the Black Panther Party were put on trial in state court. It was a sensational trial that brought thousands to the New Haven Green and forced the shutdown of Yale University. Gov. John Dempsey ended up calling in the National Guard to maintain order.

Bobby Seale, the founder and chairman of the national Black Panther Party, was accused of ordering New Haven chapter members to kill 24-year-old Alex Rackley, a member of the Black Panthers who they believed had given New York police information about a bombing plot the panthers group had planned for New York City.

Rackley had been found dead in a swamp near the Coginchaug River in Middlefield, his body riddled with bullets, his hands bound and a wire wrapped around his neck.

Koskoff and his father represented Lonnie McLucas, a New Haven party member accused of killing Rackley.

Every morning, Michael Koskoff and his father would wade through the crowds to get into the New Haven courthouse.

McLucas, who claimed he was coerced by the Panthers to take part in Rackley’s murder, was found guilty of a lesser charge of conspiracy to commit murder. He was sentenced to 12 years in prison.

Bobby Seale was acquitted of all charges.

“It is thrilling to have participated in one of the important trials of the last 50 years,” Koskoff said later in an interview. “My father and I set out to prove that a black radical could receive a fair trial and we succeeded. We did our part and fought for our client’s right to a fair trial. The system worked.”

Shortly after that trial, a group of black Bridgeport police officers asked Michael Koskoff to represent them in a civil rights case against the department.

The case, Bridgeport Guardians v. Civil Service Commission, resulted in a court order requiring the city to hire and promote more minorities in the police department.

“It’s a sad day in Bridgeport,” said retired Bridgeport Police Lt. Ron Bailey, a former Guardians president.

“Michael Koskoff addressed discrimination in the Bridgeport Police Department and did so much for the community. He would call us up to deliver toys to children in the city,” Bailey said.

Koskoff’s first civil case was against Bridgeport Hospital, the place where he was born, and a doctor there who failed to administer a test to a newborn baby. If the test had been given, the baby probably would have avoided brain damage, he said. And he found a doctor to testify to that effect.

“Suing a doctor — it just seemed wrong,” Koskoff said later about his first lawsuit. He said he then thought of the child and the child’s parents and what they were facing in life.

In 1999, Koskoff won what was, at the time, the largest personal-injury verdict in the state’s history when jurors awarded $27 million to his client, William Jacobs, for a botched heart operation at Yale New Haven Hospital.

In addition to his wife, Rosalind, Koskoff is survived by four grown children: Sarah, an actress; Juliet, a lawyer in New York; Jacob, a screenwriter in Los Angeles, and Joshua, a senior partner in the Koskoff law firm and Westport resident.