In 1961, Garrison was elected as the city's district attorney. He developed a good reputation and in his first two years he never lost a case.
Jim Garrison wrote about his success: (page 26 of the Kindle version of On the Trail of the Assassins)
NEARLY THREE YEARS PASSED.
These were years of great satisfaction for me. We had rebuilt a bucolic D.A.’s office into a crackerjack operation. The office had gone three years without losing a homicide case—and it would be eight more years before we lost our first one.
Garrison's successor had a very different view:
New Orleans Times-Picayune, May 30, 1996