The organization's members played a leading role in the On-to-Ottawa Trek and made up a significant portion of the Mackenzie–Papineau Battalion, which fought on the Republican side in the Spanish Civil War.

"[2] Some of the League's earliest organized efforts took place in major cities such as Toronto, Montreal, Winnipeg and Vancouver, finding notable success among the youth of immigrant communities.

The recent success of the October Revolution (which established the USSR) and the Western response to it had great impact on some Canadian workers.

Although Canada's economy was in a boom, some youth could still remember the post-war unemployment and misery which abounded immediately after the First World War.

[3] YCL organizers in Montreal around that time included Fred Rose and Sam Carr, who would later become leaders of Canadian Communism.

[8] Informed by Vancouver's mayor that the limited scope of the Municipal Council was ill-equipped to address their claims,[9] the British Columbia branches of the YCL and the Communist Party of Canada together with the Camp Workers' Union decided to march on Ottawa, believing that only action on a national scale could motivate the Bennett Conservative government to hear their concerns.

[9] Later that year, the Bennett government fell in the election, providing impetus to the movements for public health care, education, unemployment insurance and other social safety-net reforms.

RCMP security bulletins show leading members of the YCL to have been enthusiastic proponents of the Congress and among its key organizers.

British Columbia organized their own BC Youth Congress, which was initiated by the Young Men's Christian Association (YMCA) in conjunction with the League.

"[16] In BC, League members organized "Girls Brigades" to raise aid for Spain, a solidarity effort which won worldwide attention.

After the Spanish Civil War, the YCL continued its anti-fascist actions and published a newspaper, "The Young Worker" until the League and the Communist Party were banned in 1940.

While the new NFLY grew rapidly, the Federation reconsidered this approach after the war and re-oriented itself as a communist youth organization.

The NFLY attempted to fight growing anti-Communist sentiment and isolation through efforts in the peace movement, including a campaign against the Korean War.

According to CBC news, "Young people informally affiliated with the National Federation of Labor Youth flood[ed] the streets bearing placards protesting the 3-cent candy bar price hike to 8-cents each.

"The kids' national boycott of more expensive candy was no laughing matter for stunned proprietors who watched their sales fall eighty percent overnight.

The protest was quelled, however, by the Toronto Telegram's accusations that the National Federation of Labor Youth was a communist front determined to "plant a few of the seeds of Marxism.

The YCL benefited from the proposals of the USSR which were understood as calling for an end the arms race and for disarmament by the resurgent and broad anti-war movement in the early 1980s.

The YCL also supported the developments in El Salvador and Nicaragua, sending a delegation to help with the 1989 Nicaraguan coffee harvest.

But the late 1980s were also a time of growing political and ideological disagreement within the League over the new policies of the Soviet Union, with Glasnost and Perestroika.

By the end of the split, the group nominally led by George Hewison had formed the Cecil-Ross Society while those asserting to be the "Leninist core of the Party" retained the name of the CPC.

The initial battles of the ideological dispute over the future of the Communist Party of Canada were quickly carried into the YCL.

The 1990s saw a major push of student activism as labour and social movements were invigorated to fight the massive cut backs initiated by the governing Liberal Party of Canada.

Indigenous youth were at the fore-front of the rise in aboriginal militancy from the east to the west with the so-called Oka Crisis on Mohawk land, and the Guftason Lake Standoff in unceded Secwepemc territory.

[citation needed] The convention adopted the framework for the re-establishment of the YCL especially a Constitution continuing the principles of democratic centralism.

A Declaration of Unity and Resistance recognized among other things the dynamic and militant contribution of youth in the movement; the urgency of united action against war, environmental and ecological crisis; the multi-national character of Canada; the necessity for socialism; and the relationship of the YCL with the CPC.

The 12 immediate points of resistance are: The YCL organizes regular summer camps, schools, conferences and seminars on topical issues like the economic crisis and youth.

The purpose of the convention was to elaborate the YCL-LJC's policy on current questions, debate updates to the constitution, set an organizational plan of work, elect a renewed central leadership, and develop a united, militant and activist strategy for the youth fightback.

[citation needed] Concerning Canada, the delegates outlined the role played by the YCL-LJC in the fightback against austerity and neo-liberal policies imposed by federal and provincial governments.

The delegates passed a series of votes criticizing what they described as the corporate policies of the Trudeau government and shared their concerns about the danger of the rise of the ultra-right and of fascism.

Due to the passing of Pierre Fontaine, longtime leader of the Parti communiste du Québec, and his succession by then-YCL-LJC General Secretary Adrien Welsh, a new General Secretary was due to be elected; this position was filled by Toronto club organizer Ivan Byard.