[1][2] She competed in the elite (top 16) of the World Surf League[3] and ended 2018 season in 7th place, earning Rookie of the Year.

[4] In 2019, Marks qualified as one of the two women on the United States' first surfing team to compete at the 2020 Summer Olympics in Tokyo, Japan.

Likewise, her brother, other siblings and the rest of her family have been a constant presence at her competitions, cheering her on, giving her pointers and shouldering her when she takes home a win.

[12] In April 2019, at the first event of the WSL Championship tour, Marks defeated then seven-time world champion Stephanie Gilmore at the Australian's home break of Duranbah, New South Wales in the quarter-finals of the Boost Mobile Pro Gold Coast.

“Caroline is one of those rare athletes that from when she was 12 years old it was obvious that she was going to be world champion,” said USA Surfing head coach Chris Stone.

I can't wait to see what the future holds for her.”[15] In December 2019, she finished second on the WSL Championship tour to Carissa Moore.

[18][19] Marks was the youngest surfer to qualify for the 2020 Summer Olympics postponed to July and August 2021 due to the COVID-19 pandemic.

[28] In February 2022, Marks withdrew before the second event of the season and took time away from tour "to deal with some recurring medical and health issues."