Born in D'Lo, Mississippi, Cassibry received a Bachelor of Arts degree from Tulane University in 1941 and a Bachelor of Laws from Tulane University Law School in 1943.

He was in the United States Navy during World War II, from 1944 to 1946.

[1] On October 11, 1966, Cassibry was nominated by President Lyndon B. Johnson to a new seat on the United States District Court for the Eastern District of Louisiana created by 80 Stat.

He was confirmed by the United States Senate on October 20, 1966, and received his commission on November 3, 1966.

He assumed senior status on March 15, 1984, serving in that capacity until his retirement on April 3, 1987.