2008–2011: ATP debut Kudla reached the semifinals of his second professional tour event, U.S.A. F15
ITF Futures event, held in New York in June 2008. He first played an ATP Tour main-draw match six weeks later, in doubles at the
2008 Legg Mason Tennis Classic, partnering with fellow junior
Junior A. Ore. The pair, a wildcard entry, lost their first-round match to
Lucas Arnold Ker, and
Eduardo Schwank. Two years later, he was given a wildcard for the singles main draw of the
2010 Campbell's Hall of Fame Tennis Championships and reached the second round, where he lost to fellow American
Ryan Harrison. His first tour-level doubles match win came in reaching the second round in doubles at the
2011 U.S. Men's Clay Court Championships in Houston, Texas partnering
Donald Young. Kudla reached the quarterfinals in singles at the
2011 Campbell's Hall of Fame Tennis Championships, having knocked off big-serving
Ivo Karlović in three sets, and then second seed
Grigor Dimitrov. Kudla lost to qualifier
Michael Yani in three sets in the quarterfinals. Kudla played his first
Legg Mason Tennis Classic in Washington, D.C. in 2011, losing in the first round to
Tobias Kamke.
2012–2013: Grand Slam debut In 2012, Kudla qualified for the main draw of a Grand Slam for the first time at the
Australian Open. He lost in the first round to
Tommy Haas. He qualified for the
2012 SAP Open in San Jose, California and beat
Jack Sock in the first round. In March 2012, Denis Kudla lost to
Roger Federer in the second round of
Indian Wells Masters tournament. In 2013 at the
Australian Open he lost in the first round of qualifying to
Julian Reister. Then at the
French Open he qualified for the main draw before losing to
Jan Hájek. At
Wimbledon he again qualified for the main draw and won his first Grand Slam match against
James Duckworth. He could not repeat the victory, losing to
Ivan Dodig while plagued with a back injury throughout the three sets. At the
2013 US Open, he beat
Jiří Veselý in four sets before losing to
Tomáš Berdych.
2014–2015: Wimbledon fourth round After a lackluster start to the 2014 season, he was able to qualify and win his first match at
Wimbledon against
Marsel İlhan, before falling to
Kei Nishikori. The following week, he returned to the US and won the 2014
Winnetka Challenger. He had a bout with mononucleosis, however, that caused him to miss most of the fall schedule. He returned to form in the 2015 grass-court season, making the finals of the
2015 Aegon Surbiton Trophy Challenger, before avenging his finals loss the following week to defeat
Matthew Ebden and win the first edition of the
2015 Aegon Ilkley Trophy Challenger. Based on this success, he was rewarded with a wildcard into the main draw of
Wimbledon. He began the tournament by defeating 28th seed
Pablo Cuevas despite losing the first two sets. In the following rounds, he defeated
Alexander Zverev in four sets and
Santiago Giraldo in five sets. Kudla was narrowly beaten in the fourth round by US Open champion
Marin Čilić.
2016–2018: High career singles and doubles rankings In 2016, Kudla made it to the second round of the Australian Open and lost in the first round of the year's remaining three Slams. He reached his career-high singles ranking of No. 53 on May 23, 2016. He also competed in singles at the
2016 Rio Olympics for the United States. In 2017, Kudla failed to qualify for any of the Grand Slam Tournaments. At the
2018 Australian Open, post-qualifying, Kudla beat compatriot
Steve Johnson in the first round of the tournament, and took the first two sets off of the fifth seed
Dominic Thiem in the second round. Kudla made the main draw of the
2018 French Open when he beat
Jürgen Zopp in the final round of qualifying. However he lost to the 26th seed
Damir Džumhur in the first round. He reached his career-high doubles ranking of No. 133 on August 27, 2018. He finished the year 2018 with a singles high ranking of No. 63 his best year-end ranking in his career.
2019–2021: US Open and Wimbledon third rounds Kudla made the third round of the
2019 US Open for the first time in his career defeating No. 27 seed
Dušan Lajović before losing to World No. 1
Novak Djokovic. In January 2021, Kudla tested positive for
COVID-19 during the
Australian Open qualifying event in Doha. In June at the
2021 Wimbledon Championships, he reached the third round as a qualifier, for the first time since 2015 when he reached the fourth round which was his best showing at any Grand Slam. He defeated 30th seed
Alejandro Davidovich Fokina in a five set match and veteran
Andreas Seppi in the second round. He was eventually ousted by
Novak Djokovic but not before giving a tough fight to the world No. 1 in all three sets played.
2022: Back to top 100, Miami Masters third round, Major doubles quarterfinal He returned to the top 100 at World No. 84 on 21 March 2022 following his eight Challenger title at the
2022 Arizona Tennis Classic in Phoenix. At the same tournament he also won in doubles partnering
Treat Huey. He followed that performance by a third round showing as a qualifier at the
2022 Miami Open for the first time in his career at the Masters level defeating
Shang Juncheng and 19th seed
Lorenzo Sonego before losing to fellow qualifier
Thanasi Kokkinakis. With partner
Jack Sock he reached his first Grand Slam quarterfinal at the
2022 Wimbledon Championships where they lost to sixth seeded Colombians
Juan Sebastián Cabal and
Robert Farah.
2023–2025: Two-time United Cup champion, retirement Kudla was selected as the No. 3 ATP player as part of the
2023 United Cup United States winning team. He entered the
2023 Australian Open as a lucky loser where he defeated Russian
Roman Safiullin to reach the second round for the fourth time at this Major. At the
2023 Delray Beach Open he won his opening match against
Jordan Thompson. In October 2023, he was selected again this time as the No. 2 ATP player at the
2024 United Cup as part of the US team. He qualified for the
2024 Dallas Open as a lucky loser and won his first round match against
Radu Albot before losing this time to Jordan Thompson. Ranked No. 179, he also qualified for the
2024 BNP Paribas Open. In October 2024, he was selected for the second consecutive time as the No. 2 ATP player at the
2025 United Cup as part of the team that reached again the final. Kudla and
Desirae Krawczyk beat Czechs
Patrik Rikl and
Gabriela Knutson in straight sets in the semifinal stage. Ultimately, the United States won the United Cup title for a second time defeating Poland. Right before lifting the trophy with the USA team, Kudla announced his retirement on 4 January 2025. ==Performance timelines==