Kerolin said she is "very excited to play for the club where Ronaldinho and Neymar played" after she joined Barcelona.
The Brazilian joined for a club record fee of €1.5m (£1.25m) from Manchester City, which also marks the biggest sale in Women's Super League history.
Kerolin's move to Barca comes at a crucial time for the club, who have seen Alexia Putellas, Mapi Leon and Salma Paralluelo all leave this summer.
The 26-year-old enjoyed a strong campaign with City last season, contributing to 14 goals (nine goals, five assists) in 15 WSL games as Andree Jeglertz's side ended a 10-year wait for the league title.
Kerolin also became the first player in WSL history to score a hat-trick against the reigning champions, after netting three times against Chelsea in February.
She now embarks on a new journey with Barca, where her idols Ronaldinho and Neymar both played.
"I'm very grateful for the effort Barca made to bring me here. I've had a good season at City, and I suppose it makes sense that they made this effort," said Kerolin.
"I'm coming to the best team in the world. I'm very excited to play for the club where Ronaldinho and Neymar, two of my idols, played.
"Watching Barca, I think I can improve as a player and as a person. The last two best players in the world [Putellas and Aitana Bonmati] played at Barca, and I think being here can bring me closer to that goal.
"My strength is in attack. I always like to look forward towards the goal, and also help my teammates score. I'm a very attacking player."
vuaabdipu
0
Women's football is evolving ✨️ Soon we will hear transfer deals in the tens of millions of euros and pounds
vuaabdipu
0
I hope Kerolin shines ✨️ I want to see her follow the steps of Salma Paralluelo and be as successful as her
emilola43
0
female raphinah
woocikmptz
0
you're welcome to Camp Nou: wishing best of luck
Suarezzy
1
beautiful culers 💕
Zeediklpyz
1
You’re welcome to dismantle Real Madrid women lol 😆