The union's general secretary delivered the first Tom Maguire Memorial Lecture at Chapel FM Arts Centre in Seacroft between noon and 1.30pm.
Earlier in the day he showed up to support RMT union members striking outside Leeds Station, and went on to Beckett Street Cemetery where he and Leeds East MP Richard Burgon left red roses at Maguire's grave.
Maguire, who was found at his Burmantofts home "dead and alone" aged just 29, played a pivotal role in 19th century industrial action in the city - and was a key figure in the 1890 gas worker strike dubbed the Battle of Leeds a few years before his death.
Addressing the sold-out lecture, Mr McCluskey said: "It's high time he and his work is properly recognised."
He told the audience how socialist Maguire galvanised workers and opposed Liberal rulers, reaching out to the community to fight for the rights of Jewish tailors and other workers in the city.
Such contributions led to the development of the labour and trade union movement in general and the eventual election of the Labour Party, Mr McCluskey suggested.
The lecture also focused on the role of unions in the modern world, and Mr McCluskey said that while Leeds was known as "the city that made everything," in recent years there had been a "significant swing" towards digital and automated workplaces.
He said 650,000 of the Unite members were at high risk of losing their jobs through automation, and that the union was "modernising and making itself absolutely relevant to this modern world of work".
In response to an audience member's question about Labour-run councils, Mr McCluskey also expressed a desire for local authorities to use reserves to fight government cutbacks.
Saying that while some see the reserves as a fund for "a rainy day", he added: "It's teeming out there now. [They should] use the reserves in the hope that the cavalry's coming over the hill in the guise of Jeremy Corbyn.
"There are huge reserves in some councils - not all councils - but in some councils."
He added: "I would like Labour councils to be less enthusiastic about implementing Tory cuts and I would like people to examine the issue of using the reserves and like to see if Labour councils can work closer together."
It is not yet known whether the Tom Maguire Memorial Lecture, which was organised by Mr Burgon and his office employee Emily Coatman, will be annual or bi-annual.
Earlier in the day, Mr McCluskey left a message at Maguire's grave, which read: "In memory of a great socialist. In solidarity."
Mr Burgon's tribute said: "In memory of Tom Maquire's inspirational life and contribution - of his words and deeds!"