Garcia practiced appellate law with a client list that included Google, Warner Bros., and the Ford Motor Company.

[9] In February 2022, Garcia left private practice to serve as a deputy assistant attorney general in the United States Department of Justice's Office of Legal Counsel.

Garcia was part of the legal team representing El Paso County, Texas, in a suit challenging the diversion of U.S. Department of Defense funds to build a border wall.

The district court designated Sims an armed career criminal based on four convictions: two Arkansas residential burglaries and two serious drug offenses.

[14][15] In 2020, Garcia was the counsel of record in June Medical Services, LLC v. Russo, challenging Louisiana's law requiring doctors who perform abortions to have admitting privileges at a local hospital.

[4] President Biden nominated Garcia to the seat to be vacated by Judge Judith W. Rogers, who subsequently assumed senior status on September 1, 2022.

[22] During his confirmation hearing, Republican senators questioned him on cases that he was involved with that dealt with gun rights and abortion access.

[25][26] On January 3, 2023, his nomination was returned to the president under Rule XXXI, Paragraph 6 of the United States Senate; he was renominated later the same day.