The Glasgow Central MP claimed the party was on track to win next year's Westminster election and the 2016 Holyrood poll, reversing shattering defeats in the two parliaments in 2010 and 2011.
Addressing supporters at Perth Concert Hall he also argued the party had reclaimed the mantle of Scotland's progressive political force from the SNP.
He said: "We are a party on the way back into government with your support."
Mr Sarwar told activists they have "outlined the positive constitutional, economic and social alternative to independence and the Tories".
He went on: "This weekend we have taken our history back, taken our story back, taken social justice back, taken our party back.
"And with the support of the people of Scotland we will take our country back too."
His party's comeback, he said, was based on outlining "the positive constitutional, economic and social alternative to independence and the Tories".
Mr Sarwar, 31, said Scottish Labour leader Johann Lamont was "the polar opposite to Alex Salmond" and would be "the next first minister of Scotland".
He said: "She is someone who is a person of honesty, integrity, real values, real ideas, passionate, humble, modest, absolutely confident about what they believe in and confident in the values to become the next first minister of Scotland."
In an attack on the Nationalists, he said independence would not tackle problems of inequality facing Scotland.
He said: "Whenever faced with a big challenge the SNP answer is always independence.
"What would Alex Salmond or Nicola Sturgeon choose if asked - independence or eradicate child poverty across the UK?
"Independence or full employment across the UK?
"Independence or anything else?
"It would be independence every single time."
Mr Sarwar said voters faced a choice between "devolution or separation" and insisted he was confident the devolution would win out.
Speaking after MPs, MSPs and grassroots activists unanimously welcomed proposals to transfer a package of welfare and tax powers to Holyrood in the event of a No vote in the referendum, he said Labour was the "party of devolution".
He said Labour had written "Scotland's home rule story" in the past and urged Scots to "make sure that proud story doesn't end with Alex Salmond".
Mr Sarwar brought the three-day conference to a close following a question- and- answer session also included Ms Lamont and Shadow Secretary of State for Scotland Margaret Curran.
Responding to yesterday's ICM poll showing the Yes campaign closing the gap in the referendum battle, Ms Lamont said: "The need now to dispel any sense of complacency is essential."
The SNP, meanwhile stepped up their attacks on Labour's plan to hand Holyrood greater control over income tax.
It followed confusion over how Labour's pledge to restore the 10p bottom rate of tax across the UK would be affected by the devolution proposals.
SNP MSP Sandra White claimed Labour's plan was a "grubby compromise" demanded by Shadow Chancellor Ed Balls.
She added: "With a Yes vote we won't need to rely on compromises and backroom deals between Labour's warring factions, independence means that we will have all the economic powers we need to make Scotland a fairer, more prosperous country."