At the age of thirteen, Ninidze auditioned for the part of Prince Edward in Shakespeare's Richard III at Rustaveli State Academic Theater in Tbilisi, which was directed by Robert Sturua and premiered in 1979.

The production had great success, touring the UK three times, taking part in Edinburgh Festival, Glasgow Mayfest and The Roundhouse in London.

Also, he had successful collaborations in many of Jordania's later productions, such as The Diary of Anne Frank in 1989, David Kldiashvili’s Step-Mother in 1989 (which toured the UK in 1989–1990) and Hamlet in 1992.

After Hamlet premiered in 1992, Civil War broke out in Georgia leading to his emigration, and he only returned to the theater's stage playing Shylock in The Merchant of Venice in 2003 (dir.

He spent several months in Vienna playing a Serbian war survivor in Rebic’s film Yugofilm, which subsequently led to his emigration at the age of 25.

Throughout his career, he has also been active in Russian cinema and TV, landing major roles in Aleksei German’s Paper Soldier and Under Electric Clouds, Bakhtyar Khudojnazarov’s Luna Papa, and others.