The Shreveport resident succeeded Judge Edith H. Jones, who stepped down from the post she had held since January 2006.
President Bill Clinton appointed Stewart to the court in 1994. Before that, the 62-year-old served as a state judge in Caddo Parish and was elected to Louisiana's 2nd Circuit Court of Appeal.
Stewart received his undergraduate degree from Dillard University in 1971 and graduated from Loyola University's law school in New Orleans in 1974.
The 5th Circuit hears appeals in cases from Texas, Louisiana and Mississippi.
The court's chief judges can serve in the position for seven years or until they turn 70. Successors are determined by seniority, although a judge must be active and younger than 65 years old to qualify.