In 1990 an advertisement was placed in the Fosters Daily Democrat looking for people interested in playing some Sunday afternoon pick-up style baseball. Games were played at the Somersworth Pines with teams sharing equipment and enjoying a game they thought had passed them by.

The following year the League became affiliated with the Men's Senior Baseball League. The MSBL is a National organization based out of Melville, NY that allows leagues to pool insurance costs in order to make local leagues more affordable. Membership in MSBL also allows players and leagues to play in regional as well as Nationally sponsored tournaments.

The 1991 League was formed with 4-teams. Over the years the interest grew as they climbed to six teams. Presently the league has eight teams and roughly 115 participants. As the league has grown so has the need for fields. The Seacoast NH MSBL plays games locally in Somersworth (Pines, Tri-City Christian Academy), Milton Baeb Ruth Field (Located at the Town Beach) and the Rochester Babe Ruth Field.