He studied law and was admitted to the bar and commenced practice in Springfield, Tennessee, in 1893.

Subsequently, Garrett was elected to the Tennessee State senate in 1902 and again in 1904.

He was defeated for reelection in 1914 by James H. Davis and he resumed the practice of law in Houston.

In 1920, Garrett ran for election to the vacant 8th District seat which comprised the city of Houston and the surrounding counties, when Joe H. Eagle retired.

The Liberty Ship USS Daniel E. Garrett was named for the congressman and was deployed during World War II.