[2] Joseph dropped out of Landsdowne Public School after two years, at the age of 13, in order to work in sweatshops full-time for $3 a week to help support the family but continued to study at night to be a rabbi in the Orthodox tradition.
[2] His industrial experience led him to labour activism, particularly in the garment workers union where he fought for improved wages and conditions.
He attained further prominence in this role; Canadian historian Irving Abella later wrote that Salsberg was known as the "Commissar" of Southern Ontario's trade union movement.
In 1938, he was elected an alderman on Toronto's city council representing Ward 4 (which included the largely Jewish working class neighbourhoods around Spadina Avenue and Kensington Market).
Salsberg eulogized Stalin on the house floor when the Soviet leader died in 1953 and this speech was used against him in the 1955 election campaign when he was defeated by Progressive Conservative Allan Grossman.
[10] Salsberg had for several years been concerned with official antisemitism in the Soviet Union, and had confronted Canadian Communist leader Tim Buck on the subject as early as 1939.
He remained silent on the matter for several years (in part to maintain party unity during World War II), but became increasingly troubled by ongoing anti-Semitism in the 1950s.
Also disillusioned by Soviet invasion of Hungary and Khrushchev's Secret Speech, he resigned from the Communist Party upon his return to Canada (leading an exodus which included half the national executive).
The late 1950s were a period of tragedy for Salsberg: in addition to losing his belief in communism (and his seat in the legislature), his wife Dora died in 1959.
Salsberg also returned to Labour Zionism and, in his old age, was a longtime columnist for the Canadian Jewish News until shortly before his death.