Born in Vysoké Mýto, a small town in the Pardubice Region of the Czech Republic on 13 July 2002, Horníček was a youth product of Czech clubs Sokol Dobříkov and Pardubice before joining Portuguese outfit Braga on a trial loan shortly after his 17th birthday. After spending one year at Braga's Academy, the Czech goalkeeper signed on a permanent basis in what was Pardubice's biggest sale in the club's history.
Horníček was promoted to Braga's B team during the 2021/22 season, making 26 appearances in Liga 3 - Portugal's third tier.
The tall shot-stopper made his senior debut for Braga in a 5-0 win against Moitense in the Taça de Portugal as a 19-year-old before making his Primeira Liga bow in May 2022.
He established a regular role in-between the sticks during the 2024/25 season, keeping nine clean sheets in 24 competitive outings, including eight in 17 Portuguese top-flight matches.
Hornícek, who stands at 196cm tall (6 ft 6), carried out a strong campaign last term after recording 24 clean sheets in all competitions.
Braga claimed a fourth-place finish in the Portuguese top-flight, with Horníček making 12 clean sheets as Os Arcebispos qualified for the Conference League.
Horníček played an instrumental part in Braga's impressive run to the UEFA Europa League semi-finals.
He recorded seven shutouts in 14 matches - the most of any goalkeeper in last season's competition - as well as making four clean sheets in five qualifying fixtures.
Horníček has represented his country across numerous age groups ranging from U16 to U21 level before making his senior international debut in May 2026 during a 2-1 friendly win against Kosovo.
He was a member of his country's World Cup finals squad in North America but was an unused substitute for all three of Czechia's Group A fixtures.
The young 'keeper also featured at last year's European Under-21 Championship finals in Slovakia, starting in Group B fixtures against England and Germany.
Horníček becomes the third player from the Czech Republic to join Newcastle, following in the footsteps of David Rozehnal and the late Pavel Srníček, with the latter making over a half-century of clean sheets for the Magpies during eight seasons on Tyneside.
The 24-year-old, who has penned a five-year deal at St. James' Park, told newcastleunited.com: “The last few days have been an emotional rollercoaster from when I first heard about the move and now I’m so happy to be here. It’s a brilliant opportunity in a new league, which I’m very excited about.
“From the very first moment I arrived here, I received a fantastic welcome and really felt the warmth of the club. Everyone has been brilliant in helping me settle in.
“I know Newcastle is a huge football city, with 52,000 fans at St. James’ Park creating an incredible atmosphere and pushing the team every game. I can’t wait to play in front of them.”
