The second brother of Robert Baratheon, he served as Lord of the Sea in his brother's royal council and held the fiefdom of Dragonstone.After Robert's death, he proclaimed himself king with the help of the priestess Melisandre.
Since most of Baratheon's vassals chose to follow the third son Renly, he converted to the faith of R'hllor, the Lord of Light, in order to obtain the power promised by Melisandre.
He has a cold relationship with his wife, Celis, and his youngest daughter, Shireen, has scars on her face due to illness.