Playing at the Dragon Park National Football Development Centre in Newport, England went close to scoring in the first half, as Lucy Egan’s header forced a full-length diving save from Rachel Kelly.
The telling moment arrived 8 minutes into the second period, as substitute Holly Manders met Sophie Quirk’s cross with an unstoppable volley to put England ahead.
Despite the Young Lionesses losing Lucy Johnson to a second yellow card, they held on to win the cup, leaving the Republic as runners-up for the third successive season.
Scotland, who finished second last time round, had to settle for third spot after a 4-0 victory over Wales (2002). Naomi Welch featured with a hat-trick and their fourth goal came from Michaela McAlonie.
The play-off for fifth earlier saw Northern Ireland edge Wales (2001) 3-2.