Brownlow…also became a champion of the new Whig party, which organized in the 1830s in opposition to Andrew Jackson and the Democratic party. In 1839 Brownlow established his first newspaper, the Tennessee Whig, to defend both religious and political truth. Published with the motto "Cry Aloud and Spare Not," the paper soon became one of Tennessee's leading Whig organs while sustaining its editor's reputation as a reckless incendiary.

As the question of slavery's expansion became the nation's most pressing issue, [Brownlow] championed the preservation of both slavery and the Union. A slaveowner himself, he defended slavery on biblical grounds, but at the same time he condemned advocates of secession as radical fanatics who sought to dissolve the Union merely for personal gain. With the onset of the Civil War, Brownlow, despite his devotion to slavery, chose to remain loyal to the Union.

The Smith family fortune was threatened by the nationwide financial depression of the late 1830s, but Gerrit ultimately survived the crisis richer than ever. In the 1840s and 1850s his annual income from his landholdings and investments in banking and railroads typically exceeded $60,000.