The most shocking thing about Harlem gangster Ellsworth “Bumpy” Johnson is that he died like a schnook. Lauded as the Godfather of Harlem, he was the Golden Age cat with nine lives. He sidestepped some dozen shootings as if bids for his death were drops of rain.

Pimp, drug lord, numbers racketeer and peddler of protection, Johnson traveled with a straight razor and had no aversion to using it: He slashed those who crossed him and is said to have destroyed a guy’s eyeball with a spoon. Yet when it was his time to go, in 1968, he died of a heart attack. Johnson was eating a breakfast of fried chicken and eggs at Wells Restaurant in Harlem when cholesterol accomplished what his adversaries could not.

That he lived 62 years without quitting his life of crime — he was out on $50,000 bail, stemming from a narcotics rap as he ate his last meal — speaks volumes of his wits and resiliency.

“Guys who survived the crime scene in Harlem were special, powerful, strong-willed people,” Paul Eckstein, co-creator and co-writer of “Godfather of Harlem,” the Johnson bio-series starring Forest Whitaker and dropping Sunday on Epix, told The Post. Said to be one of Harlem’s best chess players, “he thought strategically and often predicted what the Mafia would do” — Johnson and the syndicate often tangled — “before they did it.”

What made him stand out in a neighborhood full of toughs is that he backed down to no one.

“Bumpy would be the first black guy to stand up to the white criminals,” said Chris Brancato, Eckstein’s partner on the series. “For that, the citizens of Harlem loved him and feared him.”

Born in Charleston, SC, in 1905, Bumpy (the nickname either stems from a bump on his head or his habit of bumping people off) was sent by his banker father to Harlem in 1919, with the hope that he would have a better life there. According to Brancato, “There was a fear that his inability to be subservient would eventually get him lynched.”

Johnson himself told a reporter that in South Carolina, he fought “daily running battles with hostile white kids in order to attend school or venture into the streets.”

But the life envisioned by Johnson’s father was not to be. By age 15, Johnson was already a prolific second-story man. One year later, Johnson and a ragtag gang were committing armed robberies, extorting and selling protection. By his 17th birthday, Bumpy was doing time at the Elmira Reformatory.

He spent his 20s in and out of jail, establishing himself as a ruthless criminal. Squaring off against an enforcer by the name of Ulysses Rollins, Bumpy slashed the man 36 times. But it was not until 1932, after 2¹/₂ years in Sing Sing on a grand-larceny conviction, that Johnson would earn his Godfather of Harlem sobriquet.

He capitalized on the fact that the numbers game was big business in the ’30s. It was essentially an illegal lottery in which thousands of locals bet from a nickel to a dollar on a three-digit number from 000 to 999. It was such a major moneymaker that the Bronx mobster Dutch Schultz wanted his piece of the $50 million-per-year industry. To get it, he ran roughshod over the numbers bosses of Harlem, giving them the option of working for him or losing their businesses altogether. Most accepted the former and took $200-per-week salaries, forsaking the thousands they earned on their own.

One who refused to buckle was Madame Stephanie St. Clair, the only female numbers runner in Harlem. A femme fatale from Martinique, she enlisted the freshly sprung Bumpy to provide protection and keep Schultz out of her coffers — even as Schultz’s gunmen shot up her spots.

Bumpy harnessed firepower of his own and operated strategically. “Bumpy kept the war in Harlem,” said Karen E. Quinones Miller, who co-wrote the book “Harlem Godfather” (no relation to the series) with Bumpy’s wife of 20 years, Mayme Johnson. “Because white men in Harlem were easily identified, he was able to go after Dutch’s gang. Bumpy’s men, on the other hand, blended in and could have been anywhere.”

The war lasted nearly three years. By the time Schultz got rubbed out in 1935 — he was shot in the men’s room of a Newark, NJ, chophouse by made men who caught wind he was plotting to kill a fed and feared the blowback — Bumpy was thriving in Harlem.

In the throes of a torrid love affair with sultry Vanity Fair editor Helen Lawrenson, the almond-eyed 5-foot-7 Bumpy looked every part the crime boss. At her direction, he had suits custom made while purchasing shirts and ties from elite haberdasher Sulka. In her book, “Stranger at the Party,” Lawrenson writes about the time he left a steak dinner for a shootout on the street. She sat nervously while hearing gunshots. Two minutes later, Bumpy returned and Lawrenson, a nervous wreck, asked what had happened. “Nothin’,” replied Bumpy. “We both missed. Now I’m gonna have a banana split. How about you?”

He controlled much of Harlem and maintained a strong relationship with mob kingpin Charles “Lucky” Luciano. “My grandfather and Lucky had respect for each other,” Raymond Anthony Hatcher Johnson, a musician and Bumpy’s great-grandson, told The Post. “They played chess together in public, outside of the old YMCA on 135th Street.”

Bumpy’s goddaughter Verna Williams told The Post that she remembered seeing him mulling over a chessboard before looking up to tell her, “If you master the game of chess, you master the game of life.”

While Bumpy curried favor with the community — he is said to have paid rent for the down and out, bought school clothes for financially struggling children (including author Miller, who grew up in Harlem) and put them through college (as he did for Eckstein’s grandmother) — he couldn’t hide his dark side. Miller recounted a shootout on Lenox Avenue in which Bumpy chased the other guy as he drove away: “Bumpy’s car got disabled. So he jumped out and ran in the street, shooting his gun as he went.”

Another time, during an altercation with a pimp named New York Charlie — “He tried to ­gorilla one of the prostitutes under Bumpy’s protection,” said Miller — Bumpy sliced him up with his straight razor. After the incident, Johnson took his victim to a hospital emergency room where Charlie was put on a stretcher.

“He said, ‘That’s the n- - - -r who did it,’ ” said Miller. “Bumpy jumped on the gurney and started punching New York Charlie in the face. The police came, knocked Bumpy out and arrested him. But by the time Bumpy went to trial [for the hospital assault and stabbing], Charlie said he had no idea what the police were talking about.”

It’s not for nothing that an assistant US attorney described Bumpy as “the most vicious and dangerous criminal in Harlem.”

Bumpy Johnson’s final stint in jail was a 10-year stretch, for conspiracy and sale of narcotics, which eventually landed him in Alcatraz. He got out in 1963 at age 56. That was when goddaughter Verna saw him for the first time. “Everybody loved Uncle Bumpy — unless you did something to him,” she told The Post. “Then he went crazy on you. He could beat you up and beat you down. My mother said that he should have been a boxer.”

On the streets of Harlem, Bumpy came home to a world where the Italian mob had cut him out of his illegal enterprises. In a canny move, he aligned himself with Malcolm X and muscled back his power base, which included an extermination company called Palmetto Chemical.

“It was likely a front — even though he had legitimate customers,” said Epstein. “I heard from one of his guys that he distributed heroin in the spray containers.”

Friends and relatives maintained that Bumpy profited from sales of heroin in Harlem but that he personally did not handle the drugs.

Before dying, he and the NYPD had a final run-in. It ended with a “French Connection”-worthy car chase that began at his Harlem apartment and ended on the Van Wyck Expressway in Queens. Police charged him with conspiracy to distribute narcotics and believed he was poised to catch a flight to the Caribbean. No drugs were found and Bumpy was cut loose on the $50,000 bail. He died before the case went to trial.

A complex man, Johnson leaves behind a mixed legacy.

“He wasn’t Robin Hood,” Eckstein said. “He lived off the poor, robbed from other gangsters and helped where he could. But after him, the idea of Harlem criminals thinking they have at least some responsibility to the community, well, it got lost.”