His father, Dr. George Coussan, a radiologist, quarterbacked the ULL Ragin' Cajuns, when the team played in the Grantland Rice Bowl in Baton Rouge in 1970.
[4][self-published source] A partner at the Lafayette real estate law firm, Andrus Boudreaux Complete Title, Coussan also co-founded Cougar Constructione.
[4][self-published source] Coussan won his seat in a runoff election held on November 21, 2015, over fellow Republican Andre' Comeaux.
He was part of the "Gang of Eight" as described by political columnist Jeremy Alford, who led the charge in 2016 to elect Taylor Barras as the first independent Speaker of the Louisiana House of Representatives, bucking the tradition of supporting the governor's chosen leader.
As a result of these and other voted during a series of special legislative sessions in his first year in office, Coussan was ranked the 12th most conservative member of the legislature by the American Conservative Union in 2016, which ranked legislators who vote "most consistently with the ideals articulated in the U.S. Constitution: limited transparent government, individual rights, personal responsibility, and lasting cultural values.