[2] Maria and her husband Henry were both "Garrisonian" abolitionists, meaning that they believed in an "immediate" and uncompromising end to slavery, brought about by "moral suasion" or non-resistance.

Gerald Sorin writes, "In [Maria's] nonresistance principles and in her 'come-outerism,' she was rigidly dogmatic and self-righteous, believing that 'when one is perfectly right, one neither asks nor needs sympathy.'"

Though Chapman came to the anti-slavery cause through her husband's family, she quickly and stalwartly took up the cause, enduring pro-slavery mobs, social ridicule, and public attacks on her character.

[4] The Chapmans became central figures in the "Boston Clique," which primarily consisted of wealthy and socially prominent supporters of William Lloyd Garrison.

In 1835, Chapman assumed the leadership of the Boston Anti-Slavery Bazaar, which had been founded the previous year by Lydia Maria Child and Louisa Loring as a major fundraising event.

Chapman said that the fair had become passé; she argued that the Anniversary—an exclusive, invitation-only soirée featuring music, food and speeches—was more au courant and would raise more funds than the bazaar.

[citation needed] For nearly 20 years, between 1839 and 1858, Chapman edited The Liberty Bell, an annual anti-slavery gift book sold at the Boston Bazaar as part of fundraising.

It was in this period that Chapman began to manifestly deviate from Garrisonian ideolog, by endorsing the Republican party and later by supporting both the American Civil War and Abraham Lincoln's proposal in 1862 for gradual compensated slave emancipation.

Unlike many Garrisonians such as Garrison himself, Chapman gave no indication of being conflicted between the principle of non-coercion and the Civil War's objective of abolishing slavery through violent force.