At a young age, Dolgopolov lived on the tour with his parents, traveling frequently and playing players such as Medvedev, Andre Agassi, and Boris Becker.

Dolgopolov made his ATP Tour debut in September 2006 at the BCR Open Romania as a qualifier, losing in the first round to Christophe Rochus.

[7] Dolgopolov started the year at the 2010 Brisbane International, where he qualified for the tournament by beating Joseph Sirianni and Kaden Hensel.

Dolgopolov qualified for the 2010 Monte-Carlo Rolex Masters with wins over Santiago Ventura and Mischa Zverev, but lost to Julien Benneteau in the first round.

Dolgopolov started off his grass-court season seeded seventh at the Aegon International, with wins over Jamie Baker, Lu Yen-hsun, and James Ward, before falling to Michaël Llodra in the semifinals, despite being 4–1 up in the second set.

Dolgopolov began 2011 at the Medibank International in Sydney, where he won the first two rounds over Bernard Tomic and top-seeded Sam Querrey, and later lost to the eventual champion, Gilles Simon, in the quarterfinals.

He beat Mikhail Kukushkin and Benjamin Becker in the first two rounds, then avenged his defeat to Jo-Wilfried Tsonga at The Championships, Wimbledon in 2010, in five sets.

He then beat Potito Starace in the quarterfinals and crushed home-town favourite Ricardo Mello to enter his first ATP tour final.

However, partnering Igor Andreev, Dolgopolov reached his first ATP tour doubles semifinal, but lost to eventual champions Oliver Marach and Leonardo Mayer.

Dolgopolov then participated in the final leg of the Golden Triangle swing in the 2011 Abierto Mexicano Telcel tournament in Acapulco, as the sixth seed.

As the 20th seed, he received a first-round bye, and then beat Romanian Victor Hănescu to reach the third round, where he faced Grand Slam champion Juan Martín del Potro.

Dolgopolov continued his form at the next Masters event, the 2011 Sony Ericsson Open in Miami, reaching the fourth round with wins against Italian Andreas Seppi and Jo-Wilfried Tsonga.

He was defeated in the first round of the 2011 Monte-Carlo Rolex Masters by Ernests Gulbis and then lost to Nikolay Davydenko in the 2011 Barcelona Open Banco Sabadell.

It was later disclosed that he was suffering from pancreatitis since the North American swing, which led him to play sparingly during the early clay season.

Entering his second final of the year, Dolgopolov played Croatian home-town favourite, former top-10 player and fourth seed Marin Čilić.

Faced with a determined opponent, Dolgopolov needed three sets to beat Čilić and win his first ATP singles title.

[11] Seeded 22nd for the 2011 US Open, Dolgopolov defeated Frederico Gil, Flavio Cipolla, and Ivo Karlović to reach the fourth round, where he faced world no.

Seeded 4th for the 2012 Brisbane International tournament, Dolgopolov defeated Alejandro Falla, Igor Andreev, Radek Štěpánek, and Gilles Simon to make it to the final, where he lost to Andy Murray.

Some of the more notable results were beating world No.21 Kevin Anderson in 2013 Rogers Cup and former top 10 player Janko Tipsarević in Japan Open (tennis) where he has reached quarterfinals.

Dolgopolov began the year at the Apia International in Sydney, losing in the quarterfinals to eventual runner-up Bernard Tomic.

During the spring clay season, the player won over Ernest Gulbis in first round of the Monte Carlo Masters, then lost to Guillermo García López.

At Nottingham he claimed wins over Donald Young, Pablo Andújar, Dominic Thiem and Yen-Hsun Lu, then lost in semifinals to Sam Querrey.

In the North American summer tour, Dolgopolov defeated Karlovich to reach round of 16 at Washington, after which he lost to Alexander Zverev.

In Cincinnati he qualified for the main draw by defeating James Ward and Santiago Giraldo, then earned a first round bye due to Kei Nishikori's withdrawal and won over Bernard Tomic, Jerzy Janowicz and Tomáš Berdych to reach the semi-finals, where he lost to world nº 1 Novak Djokovic in three sets, having won the first.

Dolgopolov won his third ATP title at the 2017 Argentina Open defeating top seeded Japanese player Kei Nishikori.

Dolgopolov announced his retirement on 1 May 2021, having played Novak Djokovic in his final match on 14 May 2018 at the Internazionali BNL d'Italia in Rome.

Their actions are weaker"[16] In his early career, Alex has played two games for his country: in 2006 he lost to Andy Murray in Odesa, in a match against Great Britain.

[17][18] On 13 March 2011 Dolgopolov stated he wants to represent Ukraine as a player, but only after the leadership of the Ukrainian Tennis Federation changes.

[citation needed] Dolgopolov suffers from a hereditary disorder known as Gilbert's syndrome, which affects his liver, blood and often causes fatigue.

[10] His condition worsens when he has to cross continents in extensive travel, requiring intravenous drug treatments and monitored diets to get himself back on track.