Sharni began studying dance at the age of 12 and studied with Australian Theatre for Young People for four year. She became a student in the Brent Street School of Performing Arts and upon leaving high school, Vinson continued her studies as a full time student with the Brent Street School.

Sharni portrayed the role of Cassie in the Australian soup opera Home and Away from 2004 to 2008. She also portrayed Lori Mandel, a pregnant woman held hostage in the season four cliffhanger of CSI New York.