Born in Rathkeale, Co. Limerick, Ireland, her parents were members of the immigrant Palatine community who became Methodists. Barbara joined the Methodist society when she was 18. In 1760 she married Paul Heck and they sailed in June for America, arriving in New York City on board the ship Pery in August 1760, along with her cousin Philip Embury, a carpenter and about 24 others. Many drifted into religious indifference and when a new group of Irish immigrants arrived in 1765 Barbara persuaded Embury to 'preach the word'. They formed the first Methodist class and two years later the first John Street Church was opened. Embury did some of the carpentry and Barbara, according to tradition, whitewashed the walls herself.
Following the arrival of the first of Wesley's missionaries in 1769, the Hecks, Emburys and others moved to Camden Valley in upstate New York and started another Methodist society. Around 1778 the Hecks fled from the American War of Independence, entering Canada at Montreal and by 1785 they and some of their friends had settled in Augusta in Grenville County in Upper Canada. The first Upper Canadian Methodist class, led by the Hecks' son, Samuel, was formed in 1788. Paul Heck died in 1795. Barbara died in 1804, with her German Bible open on her lap. In 1866 her descendants erected a cenotaph in her honour and in 1909 a more substantial monument was erected in Prescott, Ontario. The inscription credits her with bringing Methodism, in both America and Canada, into existence and notes that she 'laid the foundations others have built upon.'