Robert "Rob" Marionneaux was born October 7, 1968, in Baton Rouge, Louisiana, to Patricia Smith Marionneaux and the late Robert M. Marionneaux, Sr. of Maringouin. He is married to Keely Williams Marionneaux and they have one son, Robert M. Marionneaux, III. Rob grew up on a small farm in rural, Maringouin, Louisiana.

Rob Marionneaux was elected to the Louisiana Legislature at the age of 27 where he served one term in the Louisiana House of Representatives. In 1999 Rob was elected to the Louisiana Senate where he has become one of Louisiana’s most colorful and outspoken legislators. Sen. Marionneaux was again elected to the Louisiana Senate in 2003, and for a final term (due to term limits) in 2007.

In the Louisiana legislature Sen. Marionneaux has served as chairman of the powerful Revenue and Fiscal Affairs Committee which oversees the tax policies of the State of Louisiana as well as Louisiana’s $6.5 Billion Dollar capital outlay budget. He has served as Chairman of Judiciary B Committee which oversees the Department of Corrections, Juvenile Justice and Gaming within the State. He has served on the State Bond Commission, and has served as Parliamentarian for the Louisiana Senate.

Sen. Marionneaux has authored numerous pieces of Legislation and has been the lead author of Louisiana’s Clean Indoor Air Act, which banned smoking in restaurants, Louisiana’s Annual Sales Tax Holiday, Louisiana’s Annual 2nd Amendment Sales Tax Holiday, Louisiana’s Military Family Relief Act which affords $250,000.00 in death benefits to families of military personnel killed in the line of duty and $100,000.00 in disability benefits to persons disabled while in the line of duty. Sen. Marionneaux has been the lead author of Louisiana’s Capitol Outlay Reform legislation, as well as the lead author of legislation which affords parents a tax deduction for tuition if they choose to send their children to private schools.

Sen. Marionneaux has been a stall worth in his attempt to repeal Louisiana’s personal state income tax. In 2011, he again authored the repeal of the tax on the middle class only to see it die in the final hours of the legislative session.

He has been listed in The Baton Rouge Business Report’s class of 2006 as one of the "Top Forty Under 40" and was inducted into the Southern University Law Center’s Hall of Fame (2006).

Sen. Marionneaux is a graduate of Catholic High of Pointe Coupee, Louisiana State University in Baton Rouge, La, where he received his Bachelor of Science Degree in Criminal Justice, and a minor in psychology and sociology. He is a graduate of Southern University Law Center where he was on the Dean's List and represented the Law Center in various capacities. Based on his academic performance Rob was invited to participate in Law Review. He was also elected Vice President of the Law Center, Southern's first Caucasian student representative.

Rob is a partner in the law firm Unglesby & Marionneaux which is located in Baton Rouge, Louisiana. Sen. Marionneaux has been appointed by the Louisiana Supreme Court to various committees regarding the legal profession in Louisiana. Sen. Marionneaux and his partner, Lewis Unglesby concentrate on personal injury, wrongful death, catastrophic injury, environmental contamination and criminal defense. He has represented thousands of individuals in their quest for justice.

His hobbies include hunting, fishing, snow skiing, boating, flying and working on his cattle farm located in Grosse Tete, Louisiana. Rob is a member of St. Joseph’s Catholic Church in Grosse Tete.