Legend has it that he joined his first gang at seven years old, which was made up of Jewish boys on Myrtle street who fought their Irish Catholic rivals across the street.
Although Comer used many of his family's earlier surnames with different combinations of given names as aliases, such as Jacob Colmore, John Colmore, Jacob Comacho, Jack Comer, he most frequently went by the nickname Jack Spot. According to Comer his nickname came from always being "on the spot" when trouble arose during childhood, but others claim it was because of the mole on his cheek.
Comer was over six feet tall and said to be a good boxer, and an even better fighter.
At fifteen Comer began working for a bookie as a runner. A year later he started working the protection rackets at Petticoat Lane--a notorious outdoor market in East London in the heart of "Jack Ripper Territory", full of pickpockets and other dubious activities where an old saying says "you can expect someone to steal your petticoat at one end of the market and then sell it back to you at the other end." The market still exists today.
During the 1930s Comer was involved in many fights, slashings and other incidents of grievous bodily harm involving protection rackets with some of his closest comrades like Morris Goldstein aka "Moisha Blueball" and Bernard Schack aka "Sonny the Yank."
Although Comer had many brushes with the law, sentences for his crimes tended to be light like probation or fines, however in 1939 he was given a sentence of six months hard labour for a slashing incident at the Somerset Social Club.
Comer famously portrayed himself as a protector of the Jewish people, as a sort of "Robin Hood of the East End." True he was a protector to Jewish shopkeepers in London's East End, however, that service did come with a fee.
According to Comer, rabbis would advise their frightened congregants to seek out Comer for his protection. On that note, Comer claimed to have been a participant, "charging into the fascists" in the 1936 Battle of Cable Street, a riot in which members of the Metropolitan Police force and fascist "Blackshirts" fought in a pitched battle. Based on the historical record that the police had diverted the Blackshirts away from the planned route, this appears to be an unlikely account. Comer's claims most certainly deserve close scrutiny.
However, after World War II Comer helped fund the "43 Group" a Jewish anti-fascist organization that clashed with far right and fascist groups like the Union Movement led by Oswald Mosley.
In 1940, Comer joined the Royal Artillery for three years where his service was "not particularly distinguished."
By the late 1940s, Comer was making a fortune from the race track, "meeting anyone who crossed him with instant and savage retribution." He partnered with infamous gangster, Billy Hill and with the July 9, 1947, elimination of rivals the White family from the racing courses, there were now no serious competition from the illicit cash that poured in.
In 1948, Comer was said to have financed a bungled raid on a British Overseas Airways Corporation warehouse at Heathrow Airport in which the guards were to have their coffee drugged with phenobarbitone and be made incapacitated. Then a treasure (millions in today's dollars) of gold bouillon and jewelry would be taken. Unfortunately for the would be thieves, London's Flying Squad (a branch of London's Metropolitan Police Department who focused on "Serious and Organised Crime") got wind of the plan and went undercover in the facility. With police hiding behind packing cases, A melee ensued with massive injuries to both police and the gang. When it was over, some had escaped but eight of the would be robbers lay unconscious on the ground. There were a number of convictions and heavy sentences were handed down for the crime. Comer was never arrested or officially linked to the crime.
Also in 1954, when a Sunday People reporter named Duncan Webb wrote a series of unflattering articles about Comer accusing him of becoming too domestic and "going soft," Comer arranged a meeting with Webb and physically assaulted him resulting in a conviction for grievous bodily harm and a fine of £50.
In 1955 Comer was arrested over a knife fight with Alber Dimas, who depending on which source you believe was either working as a strong arm man for the Italian mafia and was looking to muscle in on Comer's gambling interests at the racetrack or was a bodyguard to Billy Hill. The fight was outside a nightclub in Soho called Bar Italia and "the two fought tooth and nail, inflicting serious injuries on each other." Comer was cleared of the charges with special thanks to his barrister Rose Heilbron, a Jewish lawyer, who in her later years went on to great renown as a High Court judge.
Comer's criminal career was already in great decline when in 1956, he and his wife Rita were set upon by "Mad" Frankie Fraser (a bodyguard for Billy Hill), Bobby Warren and a half dozen other men on Hill's say so-- A gang war had erupted between the former partners in crime. He was slashed and stabbed multiple times leaving gruesome scars on his face.
As a result of the attack Comer retired and it wouldn't be long now before the criminal reign of Comer and Hill would be handed over to the likes of the Richardsons and The Krays.
There are scant accounts of the rest of Comer's life but he was said to have died "bankrupt" and "powerless."