The Czech Republic international is on loan at Sparta Prague from parent club Getafe.
Jankto posted a video on Twitter on Monday where he made the announcement, with a caption at the end stating: "This is not an entertainment. The purpose of this video is to encourage others."
"I am Jakub Jankto and like everybody else, I have my strengths and I have my weaknesses," the 27-year-old said.
"I have a family and I have my friends. I have a job which I have been doing as best as I can for years with seriousness, professionalism and passion.
"Like everybody else I also want to live my life in freedom, without fears, without prejudice, without violence, but with love.
"I am homosexual and I no longer want to hide myself."
Jankto has 45 caps for the Czech Republic, including making five appearances at Euro 2020.
The former Udinese and Sampdoria midfielder joined Getafe in August 2021, before returning to his native country in a loan deal with Sparta at the start of this season, where he has one goal in 10 Czech First League appearances.
Jankto is the latest professional footballer to come out as gay following Adelaide United's Josh Cavallo in 2021 and Blackpool youngster Jake Daniels last year.
The 27-year-old received widespread support in February after coming out as gay and is spending the season on loan with the Czech side from LaLiga outfit Getafe.
However, due to health issues, Jankto will not represent the club again this season.
On Tuesday, Jankto was involved in a traffic collision and arranged a meeting with the club on Wednesday, who announced a mutual agreement was reached.
Jankto said in an Instagram post: "In recent years, and especially the last year, so many things have accumulated around me that it is better to slow down and think about my health.
"It wasn't the best sporting year for me. I am all the more saddened that my health and mental state does not allow me to continue the pursuit of the title and the cup. I can't find the words to thank Sparta so much!"
A statement issued by Sparta read: "Jakub Jankto will be absent from first team duties to deal with personal matters. During this time, Jakub will be unavailable to Sparta Prague and head coach Brian Priske for training or matches.
"Club management initiated a meeting with Jakub Jankto [on] Wednesday morning. The meeting was arranged in response to Jakub Jankto's traffic incident on Tuesday.
"After mutual agreement, it was decided that Jakub Jankto will not participate in training sessions with the first team and will concentrate on his personal situation.
"The club will not provide further information with regard to the player. We ask the public and media to not interfere in Jakub Jankto's personal life."
