The title is the fourth straight for the Generals (10-9) and they will now await the official announcement of the 32-team field on Sunday night to find out their opening round opponent.
Shenandoah (12-5) was denied its first-ever ODAC title in any sport as W&L pulled away with a three-goal run midway through the first half.
Leading 5-4 after Liz Bereit scored on a free position for the Hornets at the 21:57 mark, Margaret Klein scored twice followed by a Meade Brewster goal to push the Generals advantage to four goals.
W&L answered with another three-goal run, again keyed by two Klein tallies, to lead 11-6 with 5:31 remaining.
The opening half was a tight affair as the two teams were not separated by more than one goal the entire stanza. The visitors, who never trailed in the game, took a 3-2 lead into the halftime lockerroom thanks to a Katie Hagen tally at the halftime gun.
This goal would give the Generals the lead for good.
The two teams split 44 shots with Washington and Lee holding a 16-11 advantage in groundballs and winning 12 of 20 draw controls.
Generals goalie Cara Mulligan had 10 saves, including seven in the first half, while Ashley Cross had eight stops for the Hornets.
Notes: Sisson, Cross and Kosmowski were all named to the All-Tournament team for SU with Rebecca Dean, Emily Conway, Hagen, Brewster and Mulligan taking spots for the Generals.