He was born on March 28, 1792 in Delaware, the son of Thomas and Mary Allen M'Clintock. Thomas's father was a Presbyterian, and his mother a Quaker, although their marriage resulted in her being removed from the Quaker rolls for marrying out of meeting. Thomas became a druggist or pharmacist, which at the time would have been achieved through an apprenticeship. Thomas became a Quaker by commitment in 1811. At age twenty-two, Thomas began working as a druggist, opening his own store in Philadelphia, and six years later, in 1820, he married Mary Ann Wilson in Burlington, New Jersey. They began their life together in Philadelphia, where they lived for the first seventeen years of their marriage, and where Thomas M'Clintock began his involvement in abolitionism. During their years there, Thomas and Mary Ann had six children, five of whom lived to adulthood. In 1827, M'Clintock co-founded the Free Produce Society of Pennsylvania along with James Mott, Richard Allen, and others and became its first secretary. This predominantly Quaker movement, which included also free African Americans, was an effort to promote the exchange of goods not involving any slave labor. In doing so, the members hoped to create a demand for "free" produce. The society felt their agenda was a peaceful and reasonable way to combat slavery. Thomas applied those principles throughout his life. That same year M'Clintock was an instrumental force in the Hicksite Schism. This separation among the Quakers resulted from disagreements as to what role doctrine should play in the church, how much one should participate in social activism, and other factors. His extensive knowledge of early Quaker theology was used to form debilitating arguments against Orthodox Quakers. His arguments caused so much tension that even ten years later, in 1836, he and his family chose to move to Waterloo, New York. While there, the M'Clintocks more actively aligned themselves with William Lloyd Garrison and his American Anti-Slavery Society. The M'Clintocks participated in petition campaigns, anti-slavery fairs, hosted numerous anti-slavery speakers and were founding members of the Western New YorkAnti-Slavery Society. In 1843, Thomas was elected to the board of managers of the American Anti-Slavery Society and later served as a vice president for a number of years. M'Clintock actively championed abolition, temperance, and Native American rights. Thomas and his wife organized anti-slavery petitions, gave refuge to black children, and continued the Free Produce movement. Controversy erupted between moderate and radical members over whether the Society had the right to discipline members for individual acts. As a result, the M'Clintocks organized a new group called the Yearly Meeting of Congregational Friends, which became official in 1853 after the schism of the Society of Friends in 1848. This new group, later renamed the Friends of Human Progress in 1854, had strong ties to the Pennsylvania Yearly Meeting of Progressive Friends. Thomas's wife, Mary Ann, was a major force in organizing the Seneca Falls Convention, the first women's rights convention. She attended the famous tea party in the Hunt where the idea for a convention was first discussed. The original Declaration of Sentiments was then written at the M'Clintock house by Elizabeth Cady Stanton, Mary Ann and probably Elizabeth M'Clintock and Mary M'Clintock. Thomas may have been involved in those discussions, but there is no direct record of that. He did chair one of the sessions of the subsequent convention and gave a speech in support of the declaration. The entire M'Clintock family was involved in the convention, and they even helped to organize a follow-up convention later in August. By 1860, at age sixty-eight, Thomas M'Clintock had moved back to Philadelphia with his family. Thomas returned to his trade as a pharmacist until about 1866. He died on March 19, 1876 at age eighty-three. His wife died eight years later on May 21, 1884.
