2018: ATP debut

Kolář played his first match in an ATP tournament, after qualifying for the 2018 Swedish Open. He was defeated in straight sets by defending champion and former Top 10 member David Ferrer.

2021: Three Challenger titles

In 2021, Kolář won 3 ATP Challenger singles titles: in April in Oeiras Portugal, in August in Iasi Romania, in September in Szczecin Poland and 4 ATP Challenger doubles titles.

2022: Grand Slam debut and first ATP & Major win

In 2022, Kolář made his ATP main draw debut in doubles at Chile Open alongside Nikola Milojević. They reached the quarterfinals with a win over local wildcards Alejandro Tabilo and Gonzalo Lama.

In his fifth qualifying attempt, Kolar finally reached the main draw of the 2022 French Open with a straight sets win over Franco Agamenone for his Grand Slam main draw debut.^[1] He won his first ATP and Grand Slam match defeating home favorite and wildcard Lucas Pouille. He lost in the second round to 4th seed Stefanos Tsitsipas in four sets with three tiebreaks in a match that lasted over 4 hours.^[2]

He entered the 2022 Wimbledon Championships main draw as a lucky loser.

Singles: 19 (8 titles, 11 runner-ups)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Win	1–0	Mar 2016	Croatia F2, Poreč	Futures	Clay	Yannick Maden	4–6, 6–4, 6–2
Loss	1–1	Mar 2016	Croatia F3, Pula	Futures	Clay	Pedro Martínez	3–6, 1–6
Loss	1–2	May 2016	Ostrava, Czech Republic	Challenger	Clay	Constant Lestienne	7–6(7–5), 1–6, 2–6
Loss	1–3	May 2016	Hungary F3, Szeged	Futures	Clay	Germain Gigounon	1–6, 0–6
Win	2–3	May 2016	Czech Republic F2, Prague	Futures	Clay	Clement Geens	6–3, 6–2
Loss	2–4	Mar 2017	Croatia F2, Poreč	Futures	Clay	Riccardo Bellotti	4–6, 3–6
Loss	2–5	Apr 2017	Croatia F4, Opatija	Futures	Clay	Laslo Đere	5–7, 4–6
Loss	2–6	Apr 2017	Kazakhstan F3, Shymkent	Futures	Clay	Mario Vilella Martínez	4–6, 6–3, 0–6
Loss	2–7	Apr 2017	Kazakhstan F4, Shymkent	Futures	Clay	Danilo Petrović	6–7(3–7), 3–6
Win	3–7	Jun 2017	Poland F1, Sopot	Futures	Clay	Kamil Majchrzak	6–3, 6–2
Win	4–7	Jul 2017	Poland F5, Mrągowo	Futures	Clay	Laurynas Grigelis	7–5, 1–0 ret
Loss	4–8	Aug 2017	Poland F10, Poznań	Futures	Clay	Mats Moraing	6–7(5–7), 4–6
Loss	4–9	Sep 2017	Hungary F8, Székesfehérvár	Futures	Clay	Enrique López Pérez	1–6, 1–6
Loss	4–10	Oct 2017	Estonia F2, Tartu	Futures	Carpet (i)	Harri Heliövaara	3–6, 5–7
Win	5–10	Apr 2021	Oeiras, Portugal	Challenger	Clay	Gastao Elias	6–4, 7–5
Win	6–10	Jul 2021	Iași, Romania	Challenger	Clay	Hugo Gaston	7–5, 4–6, 6–4
Win	7–10	Sep 2021	Szczecin, Poland	Challenger	Clay	Kamil Majchrzak	7–6(7–4), 7–5
Loss	7–11	Feb 2022	Vilnius, Lithania	Challenger	Hard (i)	Liam Broady	4–6, 4–6
Win	8–11	Apr 2023	Ostrava, Czech Republic	Challenger	Clay	Máté Valkusz	6–3, 6–2

Doubles: 45 (25 titles, 20 runner-ups)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Loss	0–1	Mar 2015	Croatia F5, Pula	Futures	Clay	Dominik Süč	Ivan Sabanov Matej Sabanov	6–4, 0–6, [7–10]
Loss	0–2	Aug 2015	Poland F1, Koszalin	Futures	Clay	Petr Michnev	Grzegorz Panfil Marcin Gawron	0–6, 4–6
Win	1–2	Oct 2015	Croatia F18, Solin	Futures	Clay	Tomáš Toman	Stefan Kozlov Nino Serdarušić	6–4, 2–6, [10–6]
Loss	1–3	May 2016	Hungary F3, Szeged	Futures	Clay	Victor Vlad Cornea	Gábor Borsos Ádám Kellner	2–6, 1–6
Loss	1–4	May 2016	Czech Republic F2, Prague	Futures	Clay	Petr Michnev	Oscar Otte Andreas Mies	0–6, 4–6
Loss	1–5	Jun 2016	Prague, Czech Republic	Challenger	Clay	Matěj Vocel	Tomasz Bednarek Nikola Mektić	4–6, 7–5, [7–10]
Win	2–5	Jul 2016	Czech Republic F4, Pardubice	Futures	Clay	Jan Hernych	David Novák Roman Jebavý	6–1, 6–4
Loss	2–6	Aug 2016	Italy F24, Cornaiano	Futures	Clay	Bastian Malla	Jonathan Eysseric José Hernández-Fernández	6–7(2–7), 6–2, [4–10]
Loss	2–7	Aug 2016	Cordenons, Italy	Challenger	Clay	Roman Jebavý	Andre Begemann Aliaksandr Bury	7–5, 4–6, [9–11]
Loss	2–8	Oct 2016	Hungary F8, Balatonboglár	Futures	Clay	Pavel Nejedlý	Gábor Borsos Ádám Kellner	6–3, 2–6, [8–10]
Loss	2–9	Nov 2016	Andria, Italy	Challenger	Carpet (i)	Roman Jebavý	Wesley Koolhof Matwé Middelkoop	3–6, 3–6
Win	3–9	Mar 2017	Croatia F2, Poreč	Futures	Clay	Nino Serdarušić	Matej Sabanov Ivan Sabanov	6–3, 6–3
Win	4–9	Mar 2017	Croatia F3, Umag	Futures	Clay	Nino Serdarušić	Hernán Casanova Juan Pablo Ficovich	7–5, 6–0
Win	5–9	Apr 2017	Kazakhstan F4, Shymkent	Futures	Clay	Nino Serdarušić	Alexander Zhurbin Mario Vilella Martínez	6–2, 6–2
Win	6–9	May 2017	Samarkand, Uzbekistan	Challenger	Clay	Laurynas Grigelis	Prajnesh Gunneswaran Vishnu Vardhan	7–6(7–2), 6–3
Win	7–9	Aug 2017	Liberec, Czech Republic	Challenger	Clay	Laurynas Grigelis	Tomasz Bednarek David Pel	6–3, 6–4
Win	8–9	Aug 2017	Cordenons, Italy	Challenger	Clay	Roman Jebavý	Igor Zelenay Matwé Middelkoop	6–2, 6–3
Loss	8–10	Jan 2018	Bangkok, Thailand	Challenger	Hard	Gonçalo Oliveira	Gerard Granollers Marcel Granollers	3–6, 6–7(6–8)
Loss	8–11	Jul 2018	Båstad, Sweden	Challenger	Clay	Gonçalo Oliveira	Harri Heliövaara Henri Laaksonen	4–6, 3–6
Win	9–11	Oct 2018	Almaty, Kazakhstan	Challenger	Hard	Lukáš Rosol	Timur Khabibulin Evgeny Karlovskiy	6–3, 6–1
Win	10–11	Jan 2019	Koblenz, Germany	Challenger	Hard (i)	Adam Pavlásek	Jürgen Melzer Filip Polášek	6–3, 6–4
Win	11–11	Feb 2019	Bergamo, Italy	Challenger	Hard (i)	Laurynas Grigelis	Tomislav Brkić Dustin Brown	7–5, 7–6(9–7)
Loss	11–12	May 2019	Braga, Portugal	Challenger	Clay	Kimmer Coppejans	Gerard Granollers Fabrício Neis	4–6, 3–6
Win	12–12	Feb 2020	Bergamo, Italy	Challenger	Hard (i)	Julian Ocleppo	Luca Margaroli Andrea Vavassori	6-4, 6-3
Loss	12–13	Aug 2020	Prague, Czech Republic	Challenger	Clay	Lukáš Rosol	Pierre-Hugues Herbert Arthur Rinderknech	3–6, 4-6
Win	13–13	Sep 2020	Prostejov, Czech Republic	Challenger	Clay	Lukáš Rosol	Sriram Balaji Divij Sharan	6–2, 2–6, [10–6]
Loss	13-14	Oct 2020	Lisbon, Portugal	Challenger	Clay	Harri Heliövaara	Roberto Cid Subervi Gonçalo Oliveira	6-7(5-7), 6-4, [4-10]
Win	14–14	Nov 2020	Maia, Portugal	Challenger	Clay	Andrea Vavassori	Lloyd Glasspool Harri Heliövaara	6–3, 6-4
Win	15-14	Feb 2021	Potechefstroom, South Africa	Challenger	Hard	Marc-Andrea Hüsler	Peter Polansky Brayden Schnur	6–4, 2–6, [10–4]
Loss	15-15	Feb 2021	Potechefstroom, South Africa	Challenger	Hard	Julien Cagnina	Raven Klaasen Ruan Roelofse	4-6, 4-6
Loss	15-16	June 2021	Prostejov, Czech Republic	Challenger	Clay	Roman Jebavý	Aleksandr Nedovyesov Gonçalo Oliveira	6-1, 6-7(5-7), [6-10]
Win	16-16	Jul 2021	Poznań, Poland	Challenger	Clay	Jiří Lehečka	Karol Drzewiecki Aleksandar Vukic	6–4, 3–6, [10–5]
Win	17–16	Aug 2021	San Marino, San Marino	Challenger	Clay	Luis David Martínez	Rafael Matos João Menezes	1–6, 6–3, [10–3]
Win	18–16	Nov 2021	Bergamo, Italy	Challenger	Hard (i)	Jiří Lehečka	Lloyd Glasspool Harri Heliövaara	6-4, 6-4
Win	19–16	Jan 2022	Traralgon, Australia	Challenger	Hard	Manuel Guinard	Marc-Andrea Hüsler Dominic Stricker	6-3, 6-4
Win	20–16	Mar 2022	Zadar, Croatia	Challenger	Clay	Andrea Vavassori	Franco Agamenone Manuel Guinard	3–6, 7–6(9–7), [10–6]
Loss	20-17	April 2022	Oeiras, Portugal	Challenger	Clay	Adam Pavlásek	Nuno Borges Francisco Cabral	4-6, 0-6
Win	21–17	Jul 2022	Zug, Switzerland	Challenger	Clay	Adam Pavlásek	Karol Drzewiecki Patrik Niklas-Salminen	6–3, 7–5
Loss	21-18	Sep 2022	Tulln an der Donau, Austria	Challenger	Clay	Denys Molchanov	Alexander Erler Lucas Miedler	3–6, 4–6
Win	22–18	Sep 2022	Lisbon, Portugal	Challenger	Clay	Gonçalo Oliveira	Vladyslav Manafov Oleg Prihodko	6–1, 7–6(7–4)
Loss	22–19	Apr 2023	Barletta, Italy	Challenger	Clay	Denys Molchanov	Jacopo Berrettini Flavio Cobolli	6–1, 5–7, [6–10]
Win	23–19	Sep 2023	Tulln an der Donau, Austria	Challenger	Clay	Blaz Rola	Piotr Matuszewski Kai Wehnelt	6–4, 4–6, [10–6]
Loss	23–20	Sep 2023	Szczecin, Poland	Challenger	Clay	Sergio Martos Gornés	Andrew Paulson Vitaliy Sachko	1–6, 6–7 (6–8)
Win	24–20	Oct 2023	Lisbon, Portugal	Challenger	Clay	Karol Drzewiecki	Jaime Faria Henrique Rocha	6–2, 7–6 (7–5)
Win	25–20	Nov 2023	Matsuyama, Japan	Challenger	Hard	Karol Drzewiecki	Toshihide Matsui Kaito Uesugi	6–3, 6–2