During the scholarship year, Guidry studied classical civilizations and Roman law at the University of the Witwatersrand in Johannesburg, South Africa.

President Trump nominated Guidry to the seat vacated by Judge Kurt D. Engelhardt, who was elevated to the United States Court of Appeals for the Fifth Circuit on May 15, 2018.

[10] The Associated Press reported Judge Greg Guidry donated tens of thousands of dollars to the Roman Catholic Archdiocese of New Orleans and consistently ruled in favor of the church amid bankruptcy involving nearly 500 clergy sex abuse victims.

[11][12] About a week later, he decided on a late-night reversal to recuse himself from the bankruptcy case involving the church.

He issued his reversal with the statement, “I have decided to recuse myself from this matter in order to avoid any possible appearance of personal bias or prejudice”.