The Prime Minister delivered a stinging criticism of the SNP, and warned that Scots would only be able to make a difference to global challenges if they remained part of Britain.
In his first speech to the Scottish Labour Party conference as Prime Minister, Mr Brown urged Scots to think big and not become parochial or obsessed with "narrow" nationalism.
He contrasted his global aims of eradicating disease and providing free education for all with the SNP's desire to "put up barriers" between countries. Mr Brown surprised delegates by delivering his 45-minute speech without notes or an autocue. Instead, he paced around the Aviemore stage, describing his Scottish upbringing and his pride in his home town, Kirkcaldy, his constituency in Fife and his country.
But he then outlined his desire to take social justice around the world, pointing out the achievements of Labour over its last ten years in power and what he wanted to achieve in the future.
The Prime Minister wanted to portray the Scottish Labour Party as a big national party in an international context, particularly after its election defeat by the SNP.
The aim was for the Prime Minister's international status and his message to carry outside the conference hall, persuading disillusioned Labour voters that the party represents more, and can do more, than the SNP.
Mr Brown referred to the global challenges of climate change, disease and poverty and held up a vision of being the "first generation" to be able to tackle all of them.
But he stressed this could only be achieved if people, countries and continents worked together and did not retreat into nationalist self-interest.
Richard Baker, a Labour MSP, said of the Prime Minister's speech:
"This is exactly what we should have more of in Scotland. We have been focused on domestic policies and the debate over the constitution. What Gordon Brown did was give it an international context, showing how interdependent everything is."
This was the first time Mr Brown had taken such a "casual" approach to his delivery of a conference speech. At first, he gave the impression he was simply imitating David Cameron, the Conservative leader, who surprised the Tory conference in his first year as leader by speaking without notes or a lectern.
Whispered claims of "he's doing a Cameron" were heard around the hall as Mr Brown began his speech not from the lectern, but in front of those sitting on the stage as he spoke.
The Prime Minister's approach was less relaxed and appeared more rehearsed than Mr Cameron's, although one former aide later insisted that Mr Brown had only spent his flight from London preparing for the speech, rather than the "two weeks" he claimed Mr Cameron had spent writing his.
One side-effect of the new style of delivery was there were few gaps for applause, as Mr Brown continued to build his arguments almost without pause.
Labour delegates gave Mr Brown a routine, if not rapturous, two-minute standing ovation, which he received with his wife Sarah on the stage.
It was as if the audience had been encouraged and surprised by the style of the speech and intrigued by the content, but not energised or inspired.
When it was suggested this was an unusual style for the Prime Minister to adopt, Des Browne, the Scottish Secretary, agreed, but added: "Maybe it will become his style from now on."
As for the substance of the speech, Mr Brown has made more coruscating attacks on the SNP before, but this was the first time he has used a major speech to link the global challenges he wants to take on with the politics of nationalism.
He did not bait or berate Alex Salmond, but he did warn Labour's Scottish activists that they had to react to being in opposition by becoming the "frontline of defence", protecting the poor and the vulnerable from the policies of the SNP government.
He added: "We should stand up for the people of Scotland and for the young people of Scotland. We will be the front-line of defence for them against these SNP cuts, not just because they are wrong but because they are depriving our country of its best future."
The speech was measured and plainly delivered, with a wider, international scope than might have been expected.
It was when the Prime Minister moved on to global challenges that he became passionate about his mission to take social justice to all parts of the world, something he said could only be achieved with others.
He talked about the achievements of the G8 under British leadership, of the International Monetary Fund under British leadership and of the Bali climate-change talks, with Britain leading Europe to secure a deal on the environment.
"These were not Scottish-only policies, or English-only policies, or Welsh or Northern Irish-only policies," he said.
Mr Brown also explained his vision that "this generation should be the first" to eradicate diseases plaguing the Third World, establish free education for all and combat climate change.
These goals, he said, would only be achieved by countries, continents and governments working together.
He added: "This is an inter- dependent world. What sense would it make within these islands, as the SNP do, to separate Scotland from the rest of Britain and make it more difficult to travel and to trade? The Union enhances the influence of Scottish people and ideas."
The speech was also clearly not a Blair speech. In the passages on world poverty, for example, it contained some of the themes Mr Blair has used in the past but the argument, constantly harking back to Scottish nationalism, was very different.
The Prime Minister was also effusive in his praise of Wendy Alexander, who has endured a tough six months as Scottish Labour leader, and he claimed that she would go on to become Scotland's next First Minister.
Mr Brown also gave his full backing to the Scottish Constitutional Commission, the body set up by Ms Alexander to look into more powers for the Scottish Parliament.
Mr Brown was careful to stress his Fife background: "I am proud I attended the local school in Kirkcaldy, proud that I had the opportunity of the best healthcare when I was ill and I had the opportunity, because of a Labour government, not only to study at a great school but to go to university as well."
The Prime Minister said he wanted the same opportunities for all children, adding: "I believe in a Scotland where everyone has the chance to rise as far as their talents should take them."
THE PREMIER'S OLD SCHOOL COULD DO BETTER, SAY THE INSPECTORS
ITS motto may be "I will try my utmost" but Gordon Brown's former school needs to try harder, according to inspectors.
Attainment at Kirkcaldy High in Fife had already been judged too low, but a follow-up visit in November found that standards had dipped even further.
In 2006, an HMIE report revealed a school plagued with high staff turnover, unfilled vacancies, and a high teacher sickness rate.
This week's follow-up report says too little progress has made since then.
It said: "There had been no improvement, and in fact some decline, in levels of performance in external examinations.
"The school should continue to address the need for improvement in key areas, such as behaviour management and the quality and consistency of learning and teaching."
Former head Gwen Kinghorn retired last month before the inspector's findings were made public.
Lindsay Roy was brought in from Inverkeithing High to turn the school around.
In Inverkeithing High's most recent HMIE report last year, Mr Roy was praised as providing "strong leadership".
Ken Greer, Fife education director, admitted decisive action was required and that the council had acted swiftly.
He said: "Lindsay is one of Scotland's leading headteachers.
"Already there is evidence of improvements in staff morale, pupils' behaviour and the achievements of pupils at the first- and second-year stages."
Mr Roy said: "Collectively , we are determined to achieve the desired improvements by the time HMIE return to review progress."