[3][4] In 2020, Lagoa was a finalist to succeed Ruth Bader Ginsburg as an associate justice of the Supreme Court of the United States, which ultimately went to Amy Coney Barrett.

[11] In 2003, Lagoa became an Assistant United States Attorney for the Southern District of Florida, working in the Civil, Major Crimes, and Appellate Sections.

[14] In April 2019, Lagoa wrote for the unanimous court when it found that DeSantis had acted within his authority by suspending Sheriff Scott Israel for his response to the Stoneman Douglas High School shooting.

[15][16] In November 2019, Lagoa participated in oral arguments concerning an advisory opinion on whether the governor could require felons whom voters had re-enfranchised through 2018 Florida Amendment 4 to pay fines before being allowed to vote.

[19] On September 12, 2019, President Donald Trump announced his intent to nominate Lagoa to a seat on the United States Court of Appeals for the Eleventh Circuit.

[33] Lagoa separately wrote a special concurrence to "discuss the effect that a departure from a biological understanding of 'sex' under Title IX—i.e., equating 'sex' to 'gender identity' or 'transgender status'—would have on girls’ and women's rights and sports.

"[33] On August 21, 2023, Lagoa authored an opinion vacating a district court's preliminary injunction and allowing section 4(a)(1)-(3) of Alabama's Vulnerable Child Compassion and Protection Act to go into effect.

In allowing the law to take effect, Lagoa found it unlikely that the Constitution protects an unenumerated right of parents to treat their children with transitioning medications.

[36][37][38] The Washington Post reported that colleagues, friends, and scholars who have followed Lagoa's career describe her as "quiet and collegial, with shrewd political instincts.