Sreejesh saved South Korea's last attempt to secure the hard-fought 5-4 win in the shootout after both the teams were locked 2-2 at the end of regulation time.
Sreejesh padded away the ball from the stick of Lee Dae-Yeol to clinch the victory and seal India's place in Sunday's summit clash.
This is India's third entry into the final of the Asian Champions Trophy, whose inaugural edition it won in 2011 and were runners up to Pakistan in 2012.
Later in the day, defending champions Pakistan avenged their loss to hosts Malaysia in the opening match when they prevailed 3-2 in the penalty shootout of the second semi-final after the regulation period ended in a 1-1 draw.
India will now face a Pakistan amidst the ongoing tensions between the two countries. India had earlier defeated Pakistan 2-1 in the round-robin league stage of the tournament.