After 1890, Deakin refused all offers of cabinet posts and devoted his attention to the movement for federation.
He was Victoria's delegate to the Australasian Federal Conference, convened by Sir Henry Parkes in Melbourne in 1890, which agreed to hold an intercolonial convention to draft a federal constitution.
He was a leading negotiator at the Federal Conventions of 1891, which produced a draft constitution that contained much of the Constitution of Australia, as finally enacted in 1900.
Deakin was also a delegate to the second Australasian Federal Convention, which opened in Adelaide in March 1897 and concluded in Melbourne in January 1898.
He opposed conservative plans for the indirect election of senators, attempted to weaken the powers of the Senate, in particular seeking to prevent it from being able to defeat money bills, and supported wide taxation powers for the federal government.
Deakin often had to reconcile differences and find ways out of apparently impossible difficulties.
Between and after these meetings, he travelled through the country addressing public meetings and he was partly responsible for the large majority in Victoria at each referendum.

In 1900 Deakin travelled to London with Edmund Barton and Charles Kingston to oversee the passage of the federation bill through the Imperial Parliament, and took part in the negotiations with Joseph Chamberlain, the Colonial Secretary, who insisted on the right of appeal from the High Court to the Privy Council.
Eventually a compromise was reached, under which constitutional (inter se) matters could be finalised in the High Court, but other matters could be appealed to the Privy Council.

Deakin defined himself as an "independent Australian Briton," favouring a self-governing Australia but loyal to the British Empire.
He certainly did not see federation as marking Australia's independence from Britain.
On the contrary, Deakin was a supporter of closer empire unity, serving as president of the Victorian branch of the Imperial Federation League, a cause he believed to be a stepping stone to a more spiritual world unity.
After 1890, Deakin refused all offers of cabinet posts and devoted his attention to the movement for federation. He was Victoria's delegate to the Australasian Federal Conference, convened by Sir Henry Parkes in Melbourne in 1890, which agreed to hold an intercolonial convention to draft a federal constitution. He was a leading negotiator at the Federal Conventions of 1891, which produced a draft constitution that contained much of the Constitution of Australia, as finally enacted in 1900. Deakin was also a delegate to the second Australasian Federal Convention, which opened in Adelaide in March 1897 and concluded in Melbourne in January 1898. He opposed conservative plans for the indirect election of senators, attempted to weaken the powers of the Senate, in particular seeking to prevent it from being able to defeat money bills, and supported wide taxation powers for the federal government. Deakin often had to reconcile differences and find ways out of apparently impossible difficulties. Between and after these meetings, he travelled through the country addressing public meetings and he was partly responsible for the large majority in Victoria at each referendum.
In 1900 Deakin travelled to London with Edmund Barton and Charles Kingston to oversee the passage of the federation bill through the Imperial Parliament, and took part in the negotiations with Joseph Chamberlain, the Colonial Secretary, who insisted on the right of appeal from the High Court to the Privy Council. Eventually a compromise was reached, under which constitutional (inter se) matters could be finalised in the High Court, but other matters could be appealed to the Privy Council.
Deakin defined himself as an "independent Australian Briton," favouring a self-governing Australia but loyal to the British Empire. He certainly did not see federation as marking Australia's independence from Britain. On the contrary, Deakin was a supporter of closer empire unity, serving as president of the Victorian branch of the Imperial Federation League, a cause he believed to be a stepping stone to a more spiritual world unity.
Alfred Deakin