Karen Mirijanyan was born on June 4, 1960 in Yerevan. In 1977 he graduated from Yerevan School N 55 named after Chekhov and No. 17 musical school.
In 1983 he graduated from Yerevan State Institute of Fine Arts and Theater, Kim Arzumanyan's studio.
From 1983-1987 and 1985-1986 he worked at Tbilisi State Armenian Drama Theater.
From 1986 to 1988 he worked at Yerevan State Chamber Theater.
From 1988-1991 he worked at the Yerevan "On wheels" theater-studio.
In 1993-1995 he worked at the Lunacharsky State Drama and Comedy Theater in Armavir, Russia.
In 1995-1996, as a concert host, he worked at the Armenian State Song Theater.
From 1996-1997 he worked at Nork Theater.
From 1997-1998 he worked as a head of the HayPost Cultural House.
From 2004 to 2007 he worked at Hakob Paronyan State Musical Comedy Theater.
From 2007 to 2010 he worked at Metro Theater.
Since 2010 he has been working at Yerevan Hrachya Ghaplanyan Drama Theater.
Since 2017 he has been working at Boheme Theater, where he plays in "Aunt from Paris", "We and our Lies" and "The situation has changed in the building" performances.