Councillor Aitken is standing in the newly-named Edinburgh Eastern seat at next year's Scottish Parliament elections, aiming to oust SNP justice minister Kenny MacAskill.
At a launch in Craigmillar for his campaign Cllr Aitken was also endorsed by David Johnson, chief executive of Waverley Care, and Labour's campaign manager for the Scottish elections, John Park.
Bishop Holloway, said: "During elections, both at the local and national level, there are invariably some candidates who are described as having a large 'personal' vote. In other words, irrespective of political manifestos, there are just some people one would like to see in politics because of the quality of their character and values. I believe that Ewan Aitken is such a person, and that is why I am happy to support him. I believe that Scotland will be better off having people like Ewan Aitken in her parliament."