Even before he was appointed in 2000 to the task of verifying Iraq's compliance with disarmament promises made after the 1991 Gulf war, Washington was already plunging the knife into his candidacy.
US hawks opposed his appointment saying his failure to turn up WMDs in his previous stint as head of the International Atomic Energy Agency between 1981-1997 proved he had been outwitted by the Iraqis.
From then on the relationship has been frosty at best.
Blix stayed as head of United Nations Monitoring, Verification and Inspection Commission (UNMOVIC) until the end of June 2003.
However, he was never given the opportunity to complete his brief.
He faced unrelenting criticism from Washington and was not allowed to complete weapons inspections in Iraq due to pressure from US President George Bush and British Prime Minister Tony Blair who were both pushing to proceed with an invasion.
As UNMOVIC chief, the 75-year-old father of two, changed the culture of interaction with Iraqi authorities. His calm diplomatic qualities allowed for positive results with Baghdad officials.
Walking a fine line
Blix walked a fine line between Baghdad, on the one hand, and Washington and London on the other. His diplomacy, honed from his days as a Swedish foreign minister, was put to severe test.
Blix was 'deeply frustrated' with
the US and UK administrations
After the war, Blix did not refrain from vocalising his deep-seated frustration that the case for war was "over-interpreted".
In June 2003, Blix accused the US of treating the UN as an "alien power" which it hoped would sink without trace. "I have my detractors in Washington. There are bastards who spread things around of course, who planted nasty things in the media. Not that I cared very much."
He added that as war with Iraq became imminent, Washington "leaned on" inspectors to use more damning language in their reports.
In September 2003, he said he believed that Iraq got rid of its weapons in 1991. "I am certain more and more of the conclusion that Iraq has, as they maintained, destroyed almost all of what they had in the summer of 1991."
By going to war, Blix said, the US and Britain "ignored the views of the majority" on the Security Council, leading to a "loss of legitimacy"for the invasion.
His criticisms of the Bush and Blair administrations continued well after the war, when no evidence of banned weapons programmes or weapons were found.
At one point, Blix compared Washington and London officials to medieval witch-hunters. "In the Middle Ages when people were convinced there were witches, they certainly found them. This is a bit risky."
He even said he suspected the US of having spied on him.
His book provides a blow by blow
account of the build up to war
In some of his harshest words, he spoke of the spin and hype surrounding US President George Bush and Britain's Prime Minister Tony Blair.
He compared their governments' attempts to make the case for war to an advertiser trying to sell a fridge.
"What stands accused is the culture of spin, the culture of hyping … advertisers will advertise a refrigerator in terms that we don’t quite believe in, but we expect governments to be more serious and have more credibility."
Blix also singled out Blair for criticism. Referring to the British PM's intelligence dossier of September 2002, Blix said his "intention was to dramatise it, just as vendors of some merchandise are trying to increase or exaggerate the importance of what they have."
The US-led occupation forces' failure to turn up an Iraqi WMDs programme has vindicated Blix.
Now back in Stockholm where he lives with his wife, Eva, he has taken the opportunity to document his experiences in an explosive book about the events leading up to the 2003 Iraq war.
Disarming Iraq: The Search for Weapons of Mass Destruction, reveals the extraordinary pressure British and American governments put on Blix to produce evidence of banned weapons.
With their own efforts so far having come to naught, one could say it is Blix who is enjoying the last laugh.