Reverend Leonard A. Grimes was born on November 9, 1815, in Leesburg, Virginia, to free African-American parents. Despite his free status, he was profoundly affected by the pervasive institution of slavery in the South. Witnessing the brutal realities of slavery firsthand, Grimes became a fervent abolitionist, dedicating his life to the cause of freedom.

In Washington, D.C., Grimes established himself as a hackney driver, owning several horses and carriages. This position provided him with the mobility and cover to operate as a conductor on the Underground Railroad. He used his transportation business to secretly ferry enslaved individuals from Virginia to Washington, D.C., facilitating their journey toward freedom. In 1839, his clandestine activities led to his arrest and a two-year imprisonment and assessed a $100 fine in Richmond, Virginia, for aiding a woman named Patty and her six children in their escape from slavery in Loudoun County, Virginia.

During his incarceration, Grimes experienced a spiritual awakening, leading to his baptism into the Baptist faith upon his release. He was licensed to preach by a panel chaired by the president of Columbian College, a Baptist institution in the District of Columbia (now George Washington University). In 1846, seeking a more supportive environment for his abolitionist activities, Grimes relocated to Massachusetts, first settling in New Bedford.Upon, Grimes and his family moving to New Bedford, he later to Boston, MA in 1848.

In November 1848, he was ordained as the first pastor of Twelfth Baptist Church, where he continued his Underground Railroad and abolitionist activities, and he held this position for 25 years until his death in 1873. Under his leadership, the church earned the moniker "The Fugitives' Church," serving as a sanctuary for escaped slaves and a hub for abolitionist activities.

Grimes was a prominent figure in the national church community, serving as president of the American Baptist Missionary Convention and the Consolidated Baptist Conventions for several years. He was instrumental in pushing these organizations to oppose slavery, advocating for no fellowship with slave-holding ministries.

His commitment to the abolitionist cause extended beyond his pastoral duties. Grimes actively opposed the Fugitive Slave Act; a law that allowed slave owners with the assistance of federal agents and the court, to arrest escaped slaves return them to slavery in the South. Grimes was actively involved in significant fugitive slave cases, including those of Shadrach Minkins, Thomas Sims, and Anthony Burns. In the case of Anthony Burns, an escaped slave who became a member of Grimes's church in 1854, Grimes led efforts to secure his freedom after Burns was arrested under the Fugitive Slave Act. Although the legal battle was lost, Grimes raised sufficient funds to purchase Burns's freedom, highlighting his unwavering dedication to justice.

During the Civil War, Grimes was a key advocate for the enlistment of African Americans in the Union Army. 

Grimes also believed that blacks should be allowed to bear arms in the Civil War. Grimes appealed directly to the Governor of Massachusetts and as a result of his efforts, blacks earned the right to bear arms and join the Civil War. He played a significant role in recruiting soldiers for the 54th Regiment Massachusetts Volunteer Infantry, one of the first African-American regiments in the Civil War, encouraging members of his congregation and the broader community to join the fight for freedom.

Grimes's personal life was marked by his marriage to Octavia Grimes, who was a pillar of strength in his life and ministry. Together, they had four children: Emma, John, Leonard, and Julia. Octavia was deeply involved in church initiatives, supporting her husband's abolitionist work and contributing to the church’s efforts in aiding the oppressed.

Rev. Leonard A. Grimes passed away on March 14, 1873, in East Somerville, Massachusetts. His legacy as a pastor, abolitionist, and community leader continues to be remembered and honored. In recognition of his contributions, the City of Somerville unveiled Leonard Grimes Park on July 29, 2024, at 31 Tufts Street. The ribbon-cutting ceremony was attended by city officials, local activists, and community members. This park stands as a lasting tribute to Grimes's tireless fight for justice and equality and serves as a space for reflection and community gathering.

By naming the park in his honor, the city of Somerville ensures that Rev. Grimes's legacy continues to inspire future generations. His story is a testament to the enduring power of faith, resilience, and the pursuit of freedom.