The Sparta Prague midfielder released a video on social media on Monday saying that he wants to live his life "in freedom" and that he no longer wants to "hide" himself.
He said: "Like everybody else, I have my strengths, I have my weaknesses, I have my family, I have my friends.
"Like everybody else, I also want to live my life in freedom. Without fears. Without prejudice. Without violence. But with love. I'm homosexual and I no longer want to hide myself."
Sparta Prague followed up Jankto's announcement by saying: "Jakub spoke openly about his sexual orientation with the club some time ago. Everything else concerns his personal life. No further comments. No more questions. You have our support. Live your life, Jacob. Nothing else matters."
Josh Cavallo announced that he is gay in October 2021 to become the first man active in professional football to be open about being gay since Justin Fashanu, who publicly shared that he is gay in 1990.
Blackpool forward Jake Daniels became the first male footballer in the UK to be open about being gay since Fashanu when he shared that information publicly in May 2022. Scottish footballer Zander Murray also announced last year that he is gay, and he is the first player open about being gay in Scotland's men's professional leagues since Fashanu, who played for Hearts in 1994.
In 2013, former U.S. men's national team midfielder Robbie Rogers came out as gay as he retired from the sport, announcing both in the same blog post.
Neymar Jr. has applauded the decision taken by Jankto to announce he is gay, saying: "It's an important day. Everyone is free, prejudices must be less important, whether it's homophobia, racism, any form of discrimination. But every human being should be free to do whatever they want. You cannot forbid anyone to be what they want to be. You have to be free."
Jankto, 27, has 45 caps for Czech Republic and played in all five of his side's matches in the European Championship in 2021 as they reached the quarterfinals.