Born in Jasper, Tennessee, Darr received a Bachelor of Laws from the Cumberland School of Law (then part of Cumberland University, now part of Samford University) in 1909.

[1] Darr was nominated by President Franklin D. Roosevelt on May 24, 1939, to the United States District Court for the Eastern District of Tennessee and the United States District Court for the Middle District of Tennessee, to a new joint seat authorized by 52 Stat.

He was confirmed by the United States Senate on May 31, 1939, and received his commission on June 2, 1939.

He was reassigned by operation of law to serve only in the Eastern District on November 27, 1940.

He assumed senior status on March 15, 1961.