John Parker was the commander of the American forces at Concord during the pivotal confrontation on April 19, 1775.

As the captain of the Lexington militia, he was instrumental in rallying local volunteers to oppose British forces. Parker is well-known for urging his men to hold their position against the approaching British troops, highlighting the significance of protecting their rights and freedoms. His leadership during the confrontation at Lexington and the following events in Concord played a pivotal role in energizing colonial resistance to British authority. Parker's actions and steadfastness came to represent the growing American commitment to independence and self-governance.