Fisher posthumously won the prize for her audiobook recording of "The Princess Diarist", a memoir culled from her diaries during her time shooting the first Star Wars film and portraying Princess Leia.
The memoir was published just five weeks before her death in December 2016 and made headlines for the details it revealed, including an on-set affair with costar Harrison Ford.
Fisher beat out Neil deGrasse Tyson, Shelly Peiken, Bruce Springsteen, Bernie Sanders and Mark Ruffalo in the category.
She was previously nominated for a Grammy in 2009 for her book, "Wishful Drinking."
"'Princess Diarist' was the last profesh(ish) thing my momby and I got to do together," she said. "I wish she was here to carry me down the red carpet in some bizarre floral ensemble but instead we'll celebrate in true Carrie style: in bed in front of the TV over cold Coca Colas and warm e cigs. I'm beyond proud."
The award was announced during the Grammys' preshow ceremony.