A 63-year-old man was fatally struck by an SUV Wednesday while trying to help his son, whose car had become stuck on an icy road in Needham.

Police said the SUV slid into Joseph Flynn of Needham after hitting a patch of black ice around 7 a.m. Flynn was pinned between the two vehicles, authorities said.

The crash occurred as much of Greater Boston was struggling with black ice on interstate highways and local streets, causing numerous crashes — many of them involving multiple vehicles.

Flynn’s wife, Sheila, said during a brief, emotional phone interview that her husband was “the kindest, sweetest, gentlest man.’’

“He loved his family,’’ she said through tears. “He was all about always taking care of everyone else, and that’s what he was doing today when it happened.’’

The Flynns have three adult children, Jessica, Stephanie, and Joseph Jr.

“Anything he could do for anybody, he did,’’ Sheila Flynn said. “He just always took care of us.’’

Flynn was an executive vice president at the Needham-based NorthStar Insurance Services Inc.

“He was someone everybody could count on,’’ said Edward Pierce, the company founder, who said he worked with Flynn for more than two decades. “He was always there for everybody, and he was always there for his kids, first and foremost. . . . And he was always a lot of fun.’’

In Needham, Police Chief John Schlittler said the driver of the SUV lost control as he neared the intersection of Brookline Street and Greendale Avenue.

“Our thoughts and prayers are with the victim’s family, their friends and relatives,’’ Schlittler said. “It just seems to really be a horrific accident.’’

Jim Collins, whose son and daughter-in-law live on Brookline Street, said his daughter-in-law, a nurse, rushed outside to help after seeing the crash. Collins said she told him the driver of the first car had called his father after sliding off the icy road into a post. After Flynn arrived, another car came over the hill and hit him, Collins said.

Richard Merson, Needham’s director of public works, said the freeze was sudden and unpredicted, and workers were just salting the streets at 7 a.m., when Flynn was killed.

Except for the Needham fatality, authorities said no serious injuries were reported in any of the crashes, including one in the northbound lanes of Interstate 95 in Wakefield between exits 39 and 40 that involved 55 vehicles and shut down the highway for about two hours. Eight people were taken to the hospital and treated for injuries that were not life-threatening, officials said.

Governor Charlie Baker defended the state’s handling of treacherous road conditions after an early morning turn in the weather led to multiple accidents during the morning commute.

“Places that were just wet became sheets of ice,’’ he said.

The problem with icy roads persisted into mid-morning. MassDOT reported nearly 300 salt and sanding crews were on the roads around 10 a.m.

In a statement, Boston Public Schools officials said nine buses were involved in ice-related accidents Wednesday morning. In just one incident, ­seven students were taken to area hospitals as a precaution, but no serious injuries were reported.

In Melrose, two or three students were taken to the hospital for minor injuries after a school bus skidded on ice, Melrose police said.

Highway administrator Thomas Tinlin said that while overnight forecasts from the National Weather Service had warned about icy road conditions in Western Massachusetts, warnings about Eastern Massachusetts did not start coming in until 4:30 a.m.

Travis Andersen and John R. Ellement of the Globe staff contributed to this report. Maddie Kilgannon can be reached at maddie.kilgannon @globe.com. Follow her on Twitter @MaddieKilgannon. Evan Allen can be reached at evan.allen@globe.com. Follow her on Twitter @evanmallen.