Vinson portrayed the role of Cassie Turner in the Australian soap opera Home and Away from 2004 to 2008. She joined the show permanently in December 2004, having previously appeared twice on the show as a minor character and auditioning for the role of Martha McKenzie but losing out to Jodi Gordon. In 2006 Vinson was nominated for a TV Week Logie Award for Best New Talent for her performance in Home and Away. In April, 2008 Sharni announced she would be leaving the series to pursue a career in America.
She portrayed the role of Lori Mandel, a pregnant woman held hostage in a bank in CSI:NY. Vinson also had a guest role in episode 13 of NCIS, "Broken Bird", which first aired on 13 January 2009. She played the part of an airline hostess named Jeanette. Vinson also played a minor role in Cold Case episode "Metamorphosis" as Mia Romanov who worked at the circus.
She has also appeared in other Australian television shows such as Saturday Disney, The Footy Show, and the Princess Margaret Hospital for Children Telethon. She was also featured on the Australian televisions series Creature Features with her pet dog.
For her first film, Vinson was cast as the female lead in the third installment in the Step Up film series, titled Step Up 3D. Filming took place in late 2009 and the film was released on August 6, 2010. She was then cast as one of the leads of Forehead Crush 2, which was filmed in mid-2010 and is set to star in the action thriller No Man's Land from director Jason Cox.
