Professor Tom Devine urged those behind the push for a Glasgow monument to the 100,000 who fled to the city to escape starvation in Ireland in the 1840s to base their campaign on "evidence and analysis of what actually happened" regardless of the "uncomfortable truths" it would throw up.
Mr Devine, director of the Scottish Centre of Diaspora Studies at Edinburgh University, is regarded as the leading authority on modern Scottish history.
He welcomed plans for a monument but said far from highlighting Glasgow's generosity, almost 50,000 immigrants were sent back to Ireland. He says the massive influx of migrants between 1845 and 1849 was a watershed in anti-Irish and anti-Catholic hostility in Scotland, with sectarian tensions also imported from Ulster.
Describing the Irish Famine as "the worst human catastrophe in 19th-century Europe", he also called into question comparisons with the Great Highland Famine of the same era.
His intervention has led to calls for him to be part of the expert group deciding what the memorial should be and its setting. The idea has won cross-party and ministerial support.
It was given the go-ahead after a council motion linking it with the Scottish Highland Potato Famine.
It called for recognition of "the efforts made by Glaswegians at the time to provide relief and sanctuary to those affected, a tradition that continues now as our city and its citizens continue to provide hope and assistance to those throughout the world affected by famine today".
But Mr Devine, who has written the definitive text on the Highland Famine and researched the response in Scotland to those fleeing Ireland, said any history had to be "warts and all".
He said: "If a historical event of such magnitude and long-term importance is to be justly commemorated it must be done on a foundation of intellectual honesty and integrity.
"To allow any commemoration to be founded on comforting myth and unproven beliefs would be to dishonour the victims of those past horrors.
"It is to be hoped the organisers of any campaign will therefore base it on impartial academic evidence and analysis of what actually happened – even if that reveals some uncomfortable truths.
"To do anything else would be a scandalous betrayal of those of the past who are now deemed worthy of such public commemoration."
He added: "It is right that the idea of commemoration should be pursued. The consecutive years of unrelenting distress in the late 1840s and early 1850s were catalytic.
"Glasgow would never be the same again.
"The population surged as never before, the pressure on the primitive and undeveloped systems of health care and sanitation almost drove the city to breaking point.
"The religious map of the west of Scotland changed irrevocably and sectarianism intensified with the huge inward movement of both Catholic and Protestant Irish, bringing in their wake the ancient enmities and hatreds of the north of Ireland.
"Yet, miraculously, this vast army of stricken impoverished people and their descendants eventually contributed hugely in a myriad of positive ways to the development of Glasgow's economy, culture and values."
SNP councillor Feargal Dalton, who has spearheaded the proposal, said: "While concentrating on the positives when I moved the motion, I did allude to the negative reactions of some, which continues today in some quarters. I would be equally disappointed if any memorial did not capture all aspects of the tragic events. Similarly, any memorial shouldn't be tucked away in the corner of a museum.
"This contribution by the eminent historian, Professor Tom Devine, is extremely useful and reminds us of the need to be true to the victims and survivors of this massive human tragedy.
"I hope an invitation for Prof Devine to be formally involved in the Memorial Working Group is forthcoming."