Mr Macintosh said Scottish Labour had to be “less oppositional” and be a “more constructive” opposition, as he formally launched his campaign to lead the party.
He said that “progressive parties need to stick together” and claimed the Scottish Parliament had “lost its way” since the start of devolution with too much confrontational behaviour from MSPs.
Mr Macintosh will compete with Scottish Labour’s deputy leader Kezia Dugdale for the top job, from which Mr Murphy is stepping down later this month in the wake of the party’s near wipeout at the hands of the SNP on 7 May.
However, Mr Macintosh set out what he said would be a radically different leadership style from Labour at Holyrood in recent years, with a “less tribal and more open” approach to the SNP government.
Mr Macintosh said he was looking “well beyond next year” and stated he was “very realistic” about the Scottish Parliament elections in 2016, when Labour faces an uphill battle to overturn the SNP’s overall majority.
The Eastwood MSP said some Scots perceived that Labour had a “sense of entitlement” and was “angry and bitter” due to its hostility to the SNP, in a scathing assessment of his party’s approach since it lost power at Holyrood in 2007.
He said: “The main message I want to put across is that we would be more positive and would stop SNP bashing. We are not going to define ourselves like that. Our main campaign message won’t be vote Labour to get rid of the SNP. We need to be less tribal and more open.
“The Labour Party is a vehicle for change, but there has been this perception of us as angry, bitter and it has been said there is sense of entitlement.”
Scottish Labour will state the timetable and process for a leadership election on 13 June to succeed Mr Murphy, who narrowly avoided a vote of no confidence at the party’s ruling body last month.
Mr Macintosh said he will be a “reformist” leader as he formally launched his candidacy after meeting students at Glasgow University yesterday. The MSP, who is Scottish Labour’s social justice spokesman, suggested there were areas of agreement between his party and the SNP – both of which place themselves on the centre-left.
He said: “There are areas of common ground such as opposing the UK government’s welfare reform agenda and resisting attacks on the more vulnerable.
“Progressive parties need to stick together.”
Mr Macintosh went on to call for the main parties in the Scottish Parliament to adopt a less adversarial style as he stated he would take a more consensual approach as Labour leader.
He said: “We need be a whole new politics, as the spirit of the Scottish Parliament was supposed to be about doing politics in a consensual way
“But it’s lost its way a bit and is more confrontational.”
When asked about the 2016 Holyrood election, he said: “My focus is not solely on next year. My goal is far more realistic than that and it is to become the constructive opposition. We would be less oppositional.”
An SNP spokesman said: “The fact is that Labour’s problems in Scotland run deep – and it will take far more than the appointment of a new leader to have any hope of solving them.”