But the jobless rate, which has fallen from a recession-high of 10 percent to 6.7 percent in February, was approaching the threshold so quickly that Fed officials believed the guideline no longer carried much weight.
So last week, at Yellen's first policy-setting meeting as Fed chair, the Federal Open Market Committee members dropped the pledge and said they would look at a wide range of factors to determine the timing of a rate hike, which would in any case not come for a "considerable time" after the Fed wraps up its bond-buying program later this year.
Kocherlakota has made it clear that he would prefer the Fed be more specific about the factors that will determine the rate- hike timetable. He has also showed no sign of deserting his conviction that the economy needs more, not less, stimulus.
A 180-degree turn
Kocherlakota has not ruled out another dissent.
(Watch: Fed's Fisher: Asset buying should end in October)
In 2011, the last year the Minneapolis Fed chief had a right to a vote on the policy-setting panel under the Fed's roster of rotating votes, Kocherlakota dissented on an August decision to pledge to keep rates near zero for at least two more years.
The economy, he thought, did not need the extra stimulus. Still, he vowed to "abide by" the pledge.
The very next month, he dissented again, but this time for a different reason: He disagreed with the Fed's decision to ease policy further with the launch of an asset-purchase program known as Operation Twist.
Kocherlakota stopped dissenting after that, even though the Fed continued to promise low rates until mid-2013 and buy assets under Operation Twist.
After a while, he even stopped publicly questioning the wisdom of easing monetary policy, and by October 2012, joined those at the Fed who fully supported further easing.
He did not dissent again until last week.