Considered a top prospect of his generation as a junior, he also made an impressive breakthrough as a young pro, reaching a career-high ranking in July 2010, before his career became largely marked by injuries, inconsistencies and a decline in his performances which coincided with the death of his father in 2011.

De Bakker received a wildcard into the ATP Amersfoort event in July 2006 and defeated top 100 and French Open Quarterfinalist Julien Benneteau in the 1st round, winning in straight sets 6–3, 6–3.

As he was the reigning Junior Champion, De Bakker received a wildcard into the main draw of the 2007 Wimbledon Championships, where he would lose in five tight sets to qualifier Wayne Arthurs.

In October 2006, De Bakker won his first senior international title in a Futures event in Albufeira, Portugal, where he beat Briton Morgan Phillips in the final.

On 5 May 2009, as a qualifier and ranked 236, he defeated the 5th seed Rainer Schüttler in the first round of the BMW Open in Münich in straight sets, before losing to former world number one, Lleyton Hewitt.

De Bakker would follow this up in the 2009 Ordina Open, by qualifying for the tournament and losing in the second round to Rainer Schüttler, after defeating Björn Phau in three tight sets.

He reached the quarter-finals of the 2010 Aircel Chennai Open, after defeating the eighth seed, Rajeev Ram, and compatriot Robin Haase, he lost to Janko Tipsarević.

De Bakker played his second Masters event two weeks later the 2010 Sony Ericsson Open, winning his first round match against Rajeev Ram in straight sets, before falling again to the eventual finalist, this time Tomáš Berdych with the same scoreline as in Indian Wells.

Following his performance at Barcelona, de Bakker received a Special Exempt to enter the main draw of Rome Masters where he faced Viktor Troicki in the first round, but retired due to a groin injury.

After defeating Viktor Troicki and Christopher Kas in the first round, they lost to the Ratiwatana twins, who entered the main tournament as lucky losers, in 4 sets.