What immediate action did the Second Continental Congress take in response to the fighting at Lexington and Concord?
It made George Washington commander of the American army.
On May 5, 1775 the second Continental Congress assembled to discuss how the country should proceed. They knew they needed a competent commander to lead the new American army. And they were not short of those who wished to lead the army. On June 15 they selected George Washington to be the commander in chief.
They also agreed that each colony would support the cause with troops and funds as it could and as was representative of their colony.