Thomas was born to John Maclellan in Castle Douglas, a small market town in Dumfries in southwest Scotland. The son of a businessman in the shoe retail industry, Thomas entered the banking world with the Bank of Scotland, later moving to Canada where he managed a bank branch in Saint John, New Brunswick.

In the Scottish town of Blairgowrie, Maclellan made a covenant with God. Having come to terms with his own fallen nature and the grace of God through Christ, he covenanted control of his life and the proceeds to God Almighty.

Thomas Maclellan immigrated to the booming industrial town of Chattanooga, Tennessee, in 1892 after a three year stay in Topeka, Kansas, and thirty years in Nova Scotia, Canada. Although he was a man of modest means, his entrepreneurial spirit was strong and his discipline was steady. He believed that God’s providence would lead him into a fruitful professional venture. In Chattanooga, Thomas invested in the fledgling, 5-year-old Provident Insurance Company that served at-risk saw mill and coal mining workers, and helped it to become prosperous and successful.

On January 31st, the Company raised $150,000 in capital by converting from a mutual assessment company to a stock company. Later that year, Thomas Maclellan became the President of Provident at the age of 73. By 1916, Provident Insurance Company had grown from a small business serving Tennesseans to a reach of 15 states. At the age of 79, Thomas passed away, but his legacy remained. As their prosperity grew, the family maintained the humble attitude of their patriarch, and preserved his commitment to glorifying God with the fruits of their work.

Incorporated in 1945 by Robert J. Maclellan, his sister Dora Maclellan Brown, and his son Robert L. Maclellan, The Maclellan Foundation, Inc. (MFI) is the largest and oldest of the Maclellan Family Foundations. In 1945, MFI’s first meeting, a total of $700 was given away to local organisations, including a grant to Maclellan’s longest grantee, the Public School Bible Committee.

Maclellan initially focused its grantmaking primarily on the Chattanooga, TN, area, supporting things such as local sanatoriums, orphanages, and community centres during the difficult time surrounding WWII. Maclellan’s first international grant was to provide relief in East Asia to those that were impacted by the war. The second international grant was given to provide Bibles for Japan in 1946 after it was first opened up.