Junior career

King began playing tennis at the age of 8 and grew up idolizing Gaël Monfils, Jo-Wilfried Tsonga, and Dustin Brown (now good friends with King). He played his first junior match in April 2006 at the age of 13 at a grade 4 tournament in Barbados. During his junior career, King made both the singles and doubles draw in 3 of the 4 boys grand slams in 2010 where he failed to make it past the first round once in the singles and made it to the second round twice in the doubles. In one tournament, he defeated future world No. 3 and 2020 US Open champion Dominic Thiem. He ended his junior career with a high ranking of 47 in both the singles and the doubles (both attained on January 4, 2010) and a record of 78–47 in singles and 81–35 in doubles.^[10]

Junior Grand Slam results – Singles:

Australian Open: A (-)
French Open: 1R (2010)
Wimbledon: 1R (2010)
US Open: 1R (2010)

Junior Grand Slam results – Doubles:

Australian Open: A (-)
French Open: 2R (2010)
Wimbledon: 2R (2010)
US Open: 1R (2010)

Professional career

King officially turned pro in 2010 at the age of 17. He was considering on playing college tennis at UCLA but made the decision to turn pro instead. Between 2011 and 2016, King would go on to make 22 ITF futures finals, winning 13 of them. These results would continuously improve his year-end ranking.

In 2014 at the Charlottesville Challenger, King threw his racket at a lineswoman which got him defaulted. The incident went widespread throughout the tennis community and internet.^[11]

In 2015 at the Citi Open, King became the first Barbadian to qualify for an ATP event. He lost to Go Soeda in the first round in straight sets.

In 2016, King made his first challenger final at the 2016 Milo Open Cali. In the final, he defeated top seed Víctor Estrella Burgos in three sets to win his first challenger title. Two weeks later, he won another challenger title at the 2016 Levene Goulding and Thompson Tennis Challenger defeating Mitchell Krueger in the final in straight sets. Two months later, he would win his third challenger title of the year at the 2016 Tiburon Challenger defeating Michael Mmoh in the final in straight sets. This would also be the year that King played in the 2016 Summer Olympics having been invited to play in the main draw in the singles. He lost to eventual quarterfinalist Steve Johnson in the first round in straight sets.

In 2017, King became the first Barbadian to win an ATP match at the Memphis Open when he won against 5th seed Bernard Tomic in straight sets. He would then follow this up with back to back second round appearances at Indian Wells and the Miami Open, losing to his idol Gaël Monfils in Indian Wells in three sets and to David Goffin in Miami both in straight sets. He reached his career high-ranking of 106 on May 8, 2017. He then went into the 2017 Wimbledon qualifying as 8th send and made it to the qualifying competition before being eliminated by Lukáš Rosol in 4 sets. He qualified for the 2017 US Open for his first and only grand slam. He lost to 4th seed Alexander Zverev in very close straight sets. He finished 2017 with a fourth challenger final at the 2017 Stockton Challenger where he lost to Cameron Norrie in straight sets.

Throughout 2018–2021 his ranking would slowly start to decline. He made two more challenger finals at the 2018 Indian Wells Challenger and the 2019 Orlando Open but lost both. He also made three more qualifying competitions at Grand Slams. Twice at the Australian Open (2018), (2019) and once at the US Open (2019). He would once again lose every single one. He did have some success in doubles, however. In the doubles, he would make 26 ITF futures finals and win 18 of them. In the challenger tour, he made seven challenger finals and won four of them. He's also known for partnering with Peter Polansky on numerous occasions.

During the COVID-19 pandemic in 2020, King underwent wrist surgery which would keep him inactive until February 2021.^[12]

Davis Cup

King made his Davis Cup debut in 2009 at the age of 16. During his time with the Barbadian Davis Cup team, he posted a win–loss record of 29–11 in singles, 11–11 in doubles, and 40–22 overall.

Singles: 32 (18–14)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Loss	0–1	Sep 2011	USA F23, Claremont	Futures	Hard	Steve Johnson	2–6, 3–6
Loss	0–2	Jul 2012	USA F20, Joplin	Futures	Hard	Sébastien Boltz	3–6, 3–6
Win	1–2	Sep 2012	Mexico F9, Manzanillo	Futures	Hard	Alexandre Schnitman	6–4, 5–0 ret.
Win	2–2	Sep 2012	Mexico F11, Manzanillo	Futures	Hard	Yoshihito Nishioka	6–0, 6–1
Loss	2–3	May 2013	Mexico F6, Puebla	Futures	Hard	Miguel Gallardo Valles	6–3, 3–6, 2–6
Win	3–3	Jul 2013	USA F20, Joplin	Futures	Hard	Alexander Sarkissian	6–3, 7–6(7–3)
Loss	3–4	Oct 2013	Mexico F16, Quintana Roo	Futures	Hard	David Souto	6–4, 4–6, 1–6
Loss	3–5	Nov 2013	Mexico F17, Quintana Roo	Futures	Hard	Michael Quintero	5–7, 6–0, 2–6
Win	4–5	Mar 2014	USA F7, Sunrise	Futures	Clay	Marc Rath	6–7(2–7), 7–5, 6–1
Win	5–5	Aug 2014	Romania F11, Iași	Futures	Clay	Filip Horanský	7–6(10–8), 6–0
Win	6–5	Aug 2014	Netherlands F6, Rotterdam	Futures	Clay	Julien Obry	2–6, 6–3, 6–2
Loss	6–6	Nov 2014	Mexico F12, Huatulco	Futures	Hard	Agustín Velotti	1–6, 6–4, 5–7
Win	7–6	Feb 2015	Panama F1, Panama City	Futures	Clay	Bastian Trinker	6–2, 6–2
Loss	7–7	Apr 2015	USA F13, Little Rock	Futures	Hard	Jason Jung	3–6, 6–4, 4–6
Win	8–7	May 2015	USA F15, Orange Park	Futures	Clay	Stefan Kozlov	6–2, 3–6, 6–0
Win	9–7	May 2015	Mexico F4, Córdoba	Futures	Hard	Ernesto Escobedo	7–5, 5–7, 6–4
Win	10–7	Jun 2015	USA F19, Tulsa	Futures	Hard	Noah Rubin	2–6, 7–5, 6–0
Win	11–7	Nov 2015	Venezuela F3, Margarita Island	Futures	Hard	Peđa Krstin	6–3, 1–0 ret.
Win	12–7	Nov 2015	El Salvador F2, La Libertad	Futures	Hard	Marcelo Arévalo	7–6(8–6), 6–4
Win	13–7	May 2016	Mexico F1, Córdoba	Futures	Hard	Adam El Mihdawy	6–1, 6–4
Loss	13–8	May 2016	Mexico F2, Pachuca	Futures	Hard	Marcelo Tomás Barrios Vera	1–6, 6–7(3–7)
Loss	13–9	Jun 2016	USA F18, Winston-Salem	Futures	Hard	Sekou Bangoura	3–6, 2–6
Win	14-9	Jul 2016	Cali, Colombia	Challenger	Clay	Víctor Estrella Burgos	5–7, 6–4, 7–5
Win	15-9	Jul 2016	Binghamton, USA	Challenger	Hard	Mitchell Krueger	6–2, 6–3
Win	16-9	Oct 2016	Tiburon, USA	Challenger	Hard	Michael Mmoh	7–6(7–2), 6–2
Loss	16-10	Oct 2017	Stockton, USA	Challenger	Hard	Cameron Norrie	1–6, 3–6
Loss	16-11	Mar 2018	Indian Wells, USA	Challenger	Hard	Martin Kližan	3–6, 3–6
Loss	16-12	Jan 2019	Orlando, USA	Challenger	Hard	Marcos Giron	4–6, 4–6
Loss	16-13	Nov 2022	M15 Santo Domingo, Dominican Republic	World Tennis Tour	Hard	Bernard Tomic	3–6, 6–4, 3–6
Loss	16-14	Jan 2023	M15 Ithaca, USA	World Tennis Tour	Hard	Radu Mihai Papoe	6–1, 4–6, 2–6
Win	17-14	Jul 2023	M15 Rochester, USA	World Tennis Tour	Clay	Ignacio Monzón	6–0, 7–6(7–2)
Win	18-14	Jul 2023	M15 Pittsburgh, USA	World Tennis Tour	Clay	Juan Carlos Aguilar	4–6, 6–3, 6–3

Doubles: 33 (22–11)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Mar 2011	Canada F1, Montreal	Futures	Hard (i)	Haydn Lewis	Maxime Authom Adrien Bossel	6–4, 2–6, [10–5]
Loss	1–1	May 2011	Venezuela F3, Caracas	Futures	Hard	Armando Javier Boschetti	Piero Luisi Román Recarte	6–3, 2–6, [8–10]
Win	2–1	May 2011	Mexico F3, Mexico City	Futures	Hard	Haydn Lewis	Christopher Díaz Figueroa Miguel Gallardo Valles	6–3, 6–4
Loss	2–2	May 2011	Mexico F4, Guadalajara	Futures	Hard	Haydn Lewis	Luis Díaz Barriga Antonio Ruiz-Rosales	6–7(7–9), 4–6
Loss	2–3	Sep 2011	Canada F5, Toronto	Futures	Clay	Sekou Bangoura	Maciek Sykut Denis Zivkovic	2–6, 1–6
Win	3–3	May 2012	Mexico F5, Celaya	Futures	Hard	Devin Britton	Ben Wagland Marious Zelba	2–6, 6–4, [10–4]
Win	4–3	May 2012	Mexico F6, Guadalajara	Futures	Hard	Devin Britton	Miguel Ángel Reyes-Varela Bruno Rodríguez	6–3, 5–7, [10–4]
Win	5–3	Jun 2012	USA F16, Indian Harbour Beach	Futures	Clay	Ruben Gonzales	Kevin King Juan Carlos Spir	6–2, 3–6, [10–4]
Loss	5–4	Jul 2012	USA F20, Joplin	Futures	Hard	Yuri Bezeruk	Harrison Adams Shane Vinsant	3–6, 6–2, [11–13]
Loss	5–5	Sep 2012	Mexico F10, Manzanillo	Futures	Hard	Christopher Díaz Figueroa	Marcelo Arévalo Miguel Ángel Reyes-Varela	1–6, 5–7
Win	6–5	Nov 2012	Mexico F14, Mérida	Futures	Hard	Yuri Bezeruk	Mauricio Astorga Marvin Barker	6–3, 6–1
Win	7–5	Jan 2013	Mexico F1, Ixtapa	Futures	Hard	Chris Letcher	Theodoros Angelinos Antoine Benneteau	6–3, 6–1
Loss	7–6	May 2013	Mexico F6, Puebla	Futures	Hard	Alex Llompart	Miguel Gallardo Valles Alan Núñez Aguilera	4–6, 1–6
Loss	7–7	Jun 2013	Greece F9, Thessaloniki	Futures	Clay	Dominik Schulz	Konstantinos Economidis Alexandros Jakupovic	1–6, 2–6
Win	8–7	Oct 2013	Mexico F14, Pachuca	Futures	Hard	Christopher Díaz Figueroa	Dean O'Brien Juan Carlos Spir	6–4, 2–6, [10–8]
Loss	8–8	Feb 2014	USA F6, Boynton Beach	Futures	Clay	Daniel Garza	Collin Altamirano Deiton Baughman	4–6, 4–6
Win	9–8	Feb 2015	USA F7, Sunrise	Futures	Clay	Cătălin Gârd	Li Yuanfeng Wil Spencer	6–2, 6–1
Win	10–8	Feb 2015	USA F8, Plantation	Futures	Clay	Cătălin Gârd	Juan Ignacio Galarza Patricio Heras	6–2, 6–4
Win	11–8	Feb 2015	Panama F1, Panama City	Futures	Clay	Julio Peralta	Iván Endara Eduardo Agustín Torre	w/o
Win	12–8	Mar 2015	USA F10, Bakersfield	Futures	Hard	Sekou Bangoura	Mitchell Krueger Connor Smith	6–4, 4–6, [10–7]
Win	13–8	Jul 2015	USA F21, Wichita	Futures	Hard	Sanam Singh	Gonzales Austin Max Schnur	6–3, 6–3
Win	14–8	Nov 2015	Venezuela F3, Margarita Island	Futures	Hard	Luis Fernando Ramírez	Christopher Díaz Figueroa Franco Feitt	6–2, 3–6, [10–7]
Win	15–8	Nov 2015	El Salvador F2, La Libertad	Futures	Hard	Emilio Gómez	Marcelo Arévalo Christopher Díaz Figueroa	6–3, 7–6(12–10)
Win	16–8	Apr 2016	Greece F3, Heraklion	Futures	Hard	Ricardo Rodríguez	Daniel Appelgren Christian Samuelsson	7–6(8–6), 6–1
Win	17–8	May 2016	Mexico F2, Pachuca	Futures	Hard	Ruben Gonzales	José Daniel Bendeck Alejandro Moreno Figueroa	6–7(2–7), 7–6(7–3), [10–4]
Win	18–8	Jul 2016	USA F23, Wichita	Futures	Hard	Sekou Bangoura	Nicolas Meister Eric Quigley	6–2, 6–3
Win	1–0	Jul 2017	Medellín, Colombia	Challenger	Clay	Miguel Ángel Reyes-Varela	Nicolás Jarry Roberto Quiroz	6–4, 6–4
Loss	1–1	Jul 2018	Gatineau, Canada	Challenger	Hard	Peter Polansky	Robert Galloway Bradley Klahn	6–7(4–7), 6–4, [8–10]
Win	2–1	Oct 2018	Stockton, USA	Challenger	Hard	Noah Rubin	Sanchai Ratiwatana Christopher Rungkat	6–3, 6–4
Loss	2–2	Mar 2019	Indian Wells, USA	Challenger	Hard	Hunter Reese	JC Aragone Marcos Giron	4–6, 4–6
Win	3–2	July 2019	Winnipeg, Canada	Challenger	Hard	Peter Polansky	Adil Shamasdin Hunter Reese	7–6(10–8), 6–3
Loss	3-3	Sep 2019	Tiburon, USA	Challenger	Hard	JC Aragone	Robert Galloway Roberto Maytín	2-6, 5-7
Win	4–3	Oct 2019	Fairfield, Canada	Challenger	Hard	Peter Polansky	Sem Verbeek André Göransson	6–4, 3–6, [12–10]

Singles

Current through the 2022 Davis Cup.