Despite his strong familial connections to the Secession Church, shortly after his University studies were complete he turned to Independent Congregationalism, as introduced to Scotland (from England) by James and Robert Haldane.

Greville Ewing, the popular minister of Lady Glenorchy's church, shortly after a chapel had been erected for him by his friends and family in Albion Street.

Although his first congregation numbered only 61, his success as a preacher was sufficient that by 1811 he and Ewing founded Glasgow's first academy for congregationalist theology students.

In 1818 he moved his congregation to a new church in West George Street capable of holding more than 1,500 people, where he remained until the closure of his ministerial life.

[1] Wardlaw strongly influenced David Livingstone, who attended his lectures in divinity, and was inspired by his campaigns against slavery to fight the African slave trade during his years as a missionary and explorer.