Born in 1980 in the family of cinematographer Dāvja Sīmaņa. In 1998, he graduated from Rīgas 2nd high school. In 2003, he graduated from Latvijas Universitäts Vēstures un philosophijas fakultātē with a bachelor's degree, in 2005 he obtained a master's degree from the History and philosophies fakultātē.At the age of 17, he started working at the studio "Kaupo Filma", where he learned the professions of cameraman and editing director. He worked as an assistant cameraman for several cameramen, including his father Dāvja Sīmaņa. In 2006, Sīmanis started working as a film director with the documentary film "Versija. LNO. He made several documentaries, but later he also made feature films — "Pelnu sanatorija" (2016), "Tēvs Nakts" (2018), "Gads before the war" (2021). Sīmanis was the author of the feature film "Emīlija. Latvijas presses karaliene" (2021) directors.Dāvja Sīmaņa's film "Marias klusums" premiered at the 74th Berlin International Film Festival.
