Sejna was born in
Liptovský Mikuláš,
Czechoslovakia. As a youth, he played in the 1993
Quebec International Pee-Wee Hockey Tournament with a team from
Poprad. Sejna attended
Colorado College, and in 2003 won the coveted
Hobey Baker Award, given annually to the most outstanding collegiate hockey player. Sejna also won the bronze medal with the
Slovak national ice hockey team in the
2003 Ice Hockey World Championship. ==Career statistics==