Three months later, Rune reached his first ATP Tour final at the 2022 Bavarian International Tennis Championships, where he won his first title and subsequently entered the top 50.

[12] On 8 June 2019 Rune defeated Toby Alex Kodat to win the 2019 French Open boys' singles title.

At the 2020 Auckland Open, Rune received a wildcard into the qualifying draw but lost to Vasek Pospisil in straight sets.

In June 2021, Rune won his first ATP Challenger title in Biella, defeating Marco Trungelliti.

145 on 23 August 2021 after winning the San Marino Open and the Verona Challenger, making him the second youngest male player in the top 150.

[24] At the 2022 Open 13, he reached his first career ATP semifinal in the doubles tournament with partner Hugo Gaston, defeating top seeds Nicolas Mahut and Pierre-Hugues Herbert and Polish pair Szymon Walków and Jan Zieliński before losing to eventual champions Andrey Rublev and Denys Molchanov.

[25] In April, Rune received a wildcard to the Bavarian International Tennis Championships, where he defeated world No.

3 Alexander Zverev in the second round for his first top 10 win in his career in straight sets to advance to his third ATP quarterfinal.

[26] He then overcame Emil Ruusuvuori[27] and Oscar Otte to reach his first career ATP singles final.

[28] There, his opponent, Botic van de Zandschulp, was forced to retire with chest pain with the scoreline at 3–4, leading the 70th-ranked Rune to become the tournament's third youngest champion in the Open Era after Guillermo Perez-Roldan in 1987.

He then stunned fourth seed Stefanos Tsitsipas to earn his third win of the season over a top 15 player to reach his first career Grand Slam quarterfinal, making him the first Danish man in singles to reach the quarterfinals of any Grand Slam tournament in the Open Era.

[33] There, he succumbed to Casper Ruud in four sets,[34] but the achievement landed Rune inside the world's top 30.

At the US Open, Rune beat Peter Gojowczyk and received a walkover from John Isner to reach the third round, where he lost again to Norrie.

He reached his second ATP final in Sofia, beating Tim van Rijthoven, Lorenzo Sonego[36] and Ilya Ivashka, then moved on to the final after defending champion and top seed Jannik Sinner retired in the middle of their match due to injury.

[40] The following week at the next tournament in Basel he beat again seventh seeded Alex de Minaur in the first round.

[41] He reached the final defeating two Frenchmen Ugo Humbert and Arthur Rinderknech, and then sixth seed Roberto Bautista Agut in the semifinals.

[54] Next he defeated another top-10 player Jannik Sinner to reach his second Masters final, before losing to Andrey Rublev in three sets.

[60] He defeated fourth seed Casper Ruud for his second top-5 win in a row to reach his second Masters final of the season.

[64] At the 2023 Queen's Club Championships he won his first match on grass as a senior against American Maxime Cressy.

[65] He reached the semifinals without dropping a set, defeating sixth seed Lorenzo Musetti in the quarterfinals.

[66] He reached the quarterfinals at Wimbledon losing to eventual champion top seed Carlos Alcaraz.

Following the results of the 2023 National Bank Open, he debuted in the top 5 of the ATP rankings for the first time on 14 August 2023 at No.

[70] During his attempted title defence at the Bavarian International Tennis Championships, he reached the semi-finals, beating both Daniel Elahí Gálán and Marc-Andrea Huesler in straight sets before losing to Jan-Lennard Struff.

[71] He then lost in the third round in both the Madrid and Italian opens, losing to Tallon Griekspoor and Sebastian Baez, respectively.

[77] Rune retired due to a knee injury during his quarterfinal match with eventual champion Arthur Fils at the Hamburg Open.

[82] At the Japan Open, Rune defeated Kei Nishikori in the quarterfinals,[83] before losing in the semifinals to eventual champion Arthur Fils.

[84] Seeded fourth, Rune reached the semifinals at the Swiss Indoors with straight sets wins over Nicolás Jarry,[85] Dominic Stricker[86] and David Goffin.

[96][97] At the time, Becker was unable to travel to the UK as a result of his criminal conviction and jail sentence for fraudulent bankruptcy.

[107] Holger Rune is an all-court player with notable defensive skills, using a compact forehand and a consistent backhand to effectively move his opponents from any part of the court.

[109][110] He currently uses the Babolat Pure Aero 98 as his racket, is endorsed by Nike for his clothing and his shoes, and is sponsored by Rolex for watches.