He said the new assembly would be "a powerful institution and I want to be part of it".
Mr Robertson's comments came after Sunday's television debate between Labour and the Scottish National Party in the old Royal High School in Edinburgh, the building earmarked as the home of Labour's proposed Scottish assembly. During the debate Mr Robertson recalled that the former Labour leader, John Smith, "lived and worked for the day he would stand here in the first parliament in 300 years".
Challenged to make a choice between Edinburgh and Westminster, he said he would be "proud to be a member of a Scottish parliament". Previously, Mr Robertson refused to say whether he would sit in the English or the Scottish capital.
Explaining his decision to end the uncertainty, he said: "I was asked a straight question and I wanted to give a straight answer. I had not realised until now that people thought that my own personal ambitions were important to the historic task of establishing a parliament." Mr Robertson said that Labour would introduce legislation to create a Scottish parliament with tax-raising powers in the first year of government. In the first-past-the-post elections to the parliament, which would take place in the existing 72 Westminster seats, he would stand for election in his Hamilton constituency. If he won and Labour had a majority, he would in effect become Scotland's first prime minister.