A two-day trial pitted the late Queen of Soul's children against each other in a battle over two handwritten versions of the singer's final wishes.
Attorneys for two of Franklin's sons had asserted their half-brother Ted White "wants to disinherit" them.
Tuesday's verdict ends a nearly five-year legal squabble within the family.
When Franklin died from pancreatic cancer in August 2018, it was widely believed she had not prepared a will to roughly $6m (£4.6m) in real estate, cash, gold records and furs, or to her music copyrights.
But, nine months later, her niece Sabrina Owens - the estate's executor at the time - discovered two separate sets of handwritten documents at the singer's home in Detroit.
One version, dated June 2010, was found inside a locked desk drawer, along with record contracts and other documents.
A newer version, from March 2014, was found within a spiral notebook containing Franklin's doodles wedged beneath the living room sofa cushions.
The 2014 will includes the quote "...being of sound mind, I write my will and testimony"
Six jurors in the city of Pontiac were tasked with determining whether or not the latter document qualifies as a valid will - a verdict they reached in less than an hour.
At the heart of the dispute are the distinctions between the two documents over what the soul superstar's four children would inherit.
Under the will now ruled valid, three sons would evenly split her music royalties and bank funds, while the youngest child Kecalf and his grandchildren would inherit his mother's primary residence, a gated mansion last valued at $1.2m (£928,000).
The 2010 document meanwhile would see a more even distribution of Franklin's assets, but requires that Kecalf and another son Edward "must take business classes and get a certificate or a degree" in order to benefit from the estate.
Kecalf and Edward have argued the newer document revokes the intentions of the older one, while their half-brother Ted argued it did not.
Taking the stand, Kecalf testified that his mother often handled business on the couch and it "doesn't strike me as odd" that a will had been found there.
During closing arguments on Tuesday, his lawyer argued the nature of the notebook's discovery was "inconsequential".
"You can take your will and leave it on the kitchen counter," said Charles McKelvie. "It's still your will."
And Edward's lawyer, Craig Smith, highlighted the document's first line - "To whom it may concern and being of sound mind, I write my will and testimony" - to argue their mother was "speaking from the grave".
"Teddy wants to disinherit his two brothers," he alleged. "Teddy wants it all."
Ted, who was his mother's touring guitarist, told the trial that Franklin would have written a will "conventionally and legally" rather than by "freehand".
His attorney Kurt Olson pointed out on Tuesday that the 2010 will was under lock and key in the house rather than under the cushions.
"They're trying to make Ted a bad guy," said Mr Olson.
Aretha's son Kecalf Franklin (right) argued her handwritten will did not strike him as odd
Franklin's eldest child Clarence, who lives in assisted housing under a guardianship, was not involved in the dispute.
He will receive an undisclosed percentage of the estate in a pre-trial agreement reached between his brothers and his guardian.
Surveys suggest more than 70% of black Americans do not have wills, in part because of centuries of distrust in the US legal system and concerns over the seizure of black-owned property.
Heirs to other prominent musicians, such as Prince and James Brown, took several years to resolve rows over their estates.
At the time of Franklin's death, her fortune was estimated to be $80m, but more recent valuations and several years of unpaid taxes have vastly reduced that number.
Nicholas Papasifakis, who currently serves as Franklin's personal representative, has previously said he will follow the court's determination and distribute her assets accordingly.
Outside court after the verdict, Kecalf Franklin said: "I'm very, very happy. I just wanted my mother's wishes to be adhered to. We just want to exhale right now. It's been a long five years for my family, my children."
Although he did not appear to speak with his brother Ted in the courtroom, he added: "I love my brother with all my heart."
-- Courtesy of BBC Sport