Bimstein was born in New York's
Lower East Side,
Manhattan, and graduated from the East Side's Public School #62 in 1910, where he competed in track, baseball and basketball. After graduation, his father moved the family to Brook Avenue and 138th Street in the Bronx, which ended Bimstein's formal education. He took to hanging out in the basement of St. Jerome's Catholic Church, where Father Ryan, the pastor, gave boxing lessons. Soon, as a bantamweight, he was fighting four-rounders at New York's Fairmont Athletic Club. He was noticed by Tom McArdle, who, later with Lou Briggs, became Bimstein's manager. But Bimstein was lazy when it came to training, he later admitted. So McArdle started using Bimstein as a sparring partner for his other fighters and eventually as a cornerman. He usually worked at Stillman's Gym daily from noon to 3 p.m. Bimstein was one of A J Liebling's most reliable informants for his boxing reports in The New Yorker during the 1930s, and his wit, wisdom and Newyorkisms are frequently quoted. Notably, he was the subject of a 5000-word profile by Liebling which appeared in the issue of 20 March 1937, pp 31-35, just a few weeks after Bimstein's 40th birthday. ″Managers pay him to do the thinking for their boys, and his relation to a fighter, particularly a young one, is approximately that of a jockey to a horse. Few fighters ever have as many as a hundred engagements in a lifetime. Whitey, since he quit boxing in proprio persona, in 1917, has thought his way through about fifteen thousand battles as a second. [...] Since history constantly repeats itself in the ring, he knows the answers to most sets of circumstances before even a boxer of genius could fathom them for himself.″ ==Champions he seconded==