A doorman shoveling the steps at his Upper East Side building died Thursday in a freak accident – when he slipped while shoveling snow, tumbled down the stairs and had his throat slit as his head crashed through a window, police said.

Longtime doorman – Miguel Gonzalez, 59 who was planning to retire soon – was clearing the stairs leading from the sidewalk to the basement lobby entrance of 333 East 93rd St. when he lost his footing around 9:30 a.m.

The impact shattered the left window pane and left a pool of blood at the bottom of the steps.

Gonzalez, who suffered deep cuts to his neck and face, was rushed to Metropolitan Hospital, but couldn’t be saved. He was pronounced dead at 10:27 a.m.

Mike Gacevic, 54, a maintenance worker at the building next door, was also cleaning snow when he heard Gonzalez’s co-worker call for help.

“He said, ‘Please help, my coworker fell down,’” Gacevic said. “I just saw him bleeding on the floor… his neck was cut a lot…he fell through the glass.”

Gacevic called Gonzalez, a married father who lived in Connecticut, “the best.”

At a snow briefing Thursday, Mayor de Blasio called the tragedy, “a very, very sad situation,” adding that “it’s another reminder to people – be very careful when you are shoveling.”

A woman who lives in the 6-story building caught the aftermath of the fall and said “It was terrible,” before she became too distraught to speak.

Miguel Modesta, 29, a building worker who works directly across the street and knows Gonzalez well, said he ran over to the scene when he saw ambulances arrive.

“He was a really nice guy. A good man. I just can’t believe it,” Modesta said of Gonzalez, a Bridgeport, resident.

“I just saw him this morning,” Modesta said.

Another building worker from across the street, who would only identify himself as Wendell, 35, said he was shoveling snow alongside Modesta when first responders arrived.

“We were told that he fell…all the way down and through the glass,” said Wendell, who described Gonzalez as “a very nice guy.”

“He was a great guy. Always said good morning to everybody. He was always joking around. He was very jovial,” Wendell said. “Everybody in the neighborhood loved him. If he was going to the store he’d buy you a coffee. This is a big shock. And it’s so sad because he was close to retiring.”

Wendell said that Gonzalez, who worked at the building for about 20 years, often talked about retiring soon.

“He was always cracking jokes. He is always upbeat. This is a major tragedy for the whole neighborhood. We need more people like him,” he said.

Modesta added that Gonzalez was the type of guy to buy breakfast for other building workers on the block.

Neighbor Denice Rich, 65, a real estate agent who lives on the E. 93rd Street block described Gonzalez as “the most friendly, sweetest, positive, happiest man…He always had a smile on his face.”

“He cared a lot for his family and he cared a lot for the people in the neighborhood. He was really genuine,” she said. “The sweetest man and a very hard worker.”

Hector Figueroa, the president of 32BJ Service Employees International Union – the union Gonzalez was a member of – expressed his condolences on Gonzalez’s passing.

“Our thoughts and prayers are with his wife and children and all those who knew and cared about him, including his coworkers and the residents of his building,” Figueroa said in a statement.

“Our union family will do all we can to support Miguel’s family in this difficult time. Our thoughts and prayers also go out to all members working hard to keep us safe during this blizzard and every day.”