Kosti Katajamaki started his career at the wheel of a Ford Escort RS 2000. The Finn took part to many events in his country and won the N2 class in the 2001 Rally Finland.
In 2002, Kosti drove in the Junior World Rally Championship at the wheel of a Volkswagen Polo. The following year, Kosti won the junior class at the Rally of Turkey, still driving a Polo.
The talented Finn was then spotted by Suzuki. Kosti drove an Ignis for the Monster Sport Europe team in the 2004 and 2005 Junior World Rally Championship. On top of his JWRC programme, Kosti also won the Finnish Rally Championship, taking three victories out of eight races at the wheel of a Peugeot 206 WRC.