Jari Manninen was born on November 5, 1985, in the small Finnish town of Viitasaari. Before his acting career, he studied at Kemi-Tornio University of Applied Sciences, where he studied screenwriting and directing. Manninen also studied creative writing at the Liminka School of Arts and acting at the Voionmaa Institute. At Kemi-Tornio University of Applied Sciences, he met Joonas Makkonen, who founded the indie group Jo-Jo the Dog Films. Manninen joined the group as an actor in their short films. Jo-Jo the Dog Films' films became widely known after receiving numerous awards at worldwide timed filmmaking competitions. In 2013, he was named Best Actor at The 24 Hour Film Race for his role in the short film "The Time Traveler with a Car" (2013).

Later that same year, Manninen also received the Best Actor award at the 100 Hour Film Race for his role in the short film "Updating Mikael" (2014). At the same event, "Updating Mikael" was awarded second best film, as well as awards for best directing, best acting ensemble, best makeup, and best poster. "Updating Mikael" shared the nomination for best music with another film. In 2014, Manninen played one of the lead roles in the horror comedy "Rabbit the Killer" (2015). It was his feature film debut. Manninen was also cast in one of the leading roles in Sami Pöyry's film "Red Noise" (2021).