"had just previously" is grammatically correct and can be used in written English.
It is typically used to refer to an action that occurred immediately before another action in the past. Here is an example: She had just previously finished her homework when her friends invited her to go out for dinner.
Kahan: We examined whether people, in judging the validity of evidence on climate change, would be more or less open-minded based on whether they had just previously been exposed to information either about geo-engineering or carbon limits.
Sony, which owns a big Hollywood studio of its own (see chart), had just previously done a deal with Comcast, America's biggest cable telephone and television provider, to sell its old movies through Comcast's network.
In the column Qandil lambasted the contradictory statements made by Aboul Gheit and Egypt's ambassador to Israel, in which the latter said Israel was a friendly state, while Aboul Gheit had just previously stated that Israel was an enemy.
On the last hour on the last day of the show, he had just previously learned that I put up a Craigslist ad that invited anyone to come to the gallery and take the semen vials.
Ct. 492, 55 L. Ed. 797, 34 L. R. A. N. S. 874), we are of opinion after examining the facts as to both of those counts that they also sustain the conviction within the principles which we have just previously stated.
There, I allowed myself to be talked into staying by the second girl, with whom I was soon making out in one of the cabs I had, just an hour previously, found so scarce.
Wal-Mart came to town in 1995 and previously had just 25 stores and less than $400 million in annual sales, says research firm Management Ventures of Cambridge, Mass.
He smiled, and although we had just met 5 minutes previously, he took my arm protectively and waved the cart on.
In a country that previously had just 10 doctors for every 100,000 people, the Ebola outbreak is likely to have an enduring effect on the local healthcare capacity.
Now he's extremely busy criticizing everything and everyone: previously he had just one party to speak ill of, now he's got five or six to badmouth!
There were photos of Iraqis with the deathlike stare of shock, stunned by the fact that something previously unimaginable had just happened to them.
