The journal was established by William Wallen and governed after his death for many years by Mrs. Wallen, his wife. Wallen began the journal after he left the Derry Journal in 1829. Wallen disagreed with the paper's new direction in favour of the Catholic Emancipation (it used to be Protestant and conservative). So, he left and started the Londonderry Sentinel. It began with a limited amount of foreign news, but it quickly became a very popular paper. Despite most of the population being illiterate, the demand for this newspaper forced Wallen to purchase a new steam-powered printing press to replace his hand driven press (Oram, The Newspaper Book, p.51).

The paper has continued into the 21st century. From 1975 to 1986 the paper wavered back and forth several times between Sentinel and Londonderry Sentinel.