Denílson and his family survived extreme poverty[5] as his parents struggled to raise him and his brothers in the dangerous favelas of São Paulo.

[9] Denílson was included in Arsenal's 19-man squad that travelled to face CSKA Moscow in the UEFA Champions League on 17 October 2006; he was named on the substitutes bench for the match, but did not play.

He made his Premier League debut for Arsenal on 30 December 2006, coming on as a substitute in a 1–0 defeat against Sheffield United at Bramall Lane.

[10] The good performance and goal seemed to have secured him a long-term place at Arsenal after it was announced that he had awarded a new contract with the club on 18 October 2007.

Denílson scored another long-range shot in a League Cup match against Sheffield United on 31 October 2007, netting the final goal in Arsenal's 3–0 win.

He received his first red card at Ewood Park against Blackburn Rovers in the League Cup quarter-finals, where he was sent off moments before extra time.

Due to the departure of many experienced players such as Mathieu Flamini, Gilberto Silva and Aliaksandr Hleb, Denílson received more playing time and partnered Cesc Fàbregas in central midfield on many occasions.

[12] He continued to play as a regular for Arsenal through December and scored his second Premier League goal in their 3–1 away win at Bolton Wanderers on 20 September 2008.

[16] Denílson came back to action against Standard Liège on 23 November where he scored Arsenal's second goal with a long-range effort in their 2–0 home win.

Denílson altogether netted a sum of six times during that season, with all these goals being long range strikes, as in the instance of a free kick upon Hull City.

[18] Due to the emergence of teenage sensation Jack Wilshere and his own injury concerns, Denílson appeared less often in the 2010–11 season, being used mostly as a substitute starting only six Barclays Premier League matches and featuring in just 16 in total.

[22] On 6 October, he scored his first goal whilst upon loan, a long range strike for São Paulo against Palmeiras in a Brazilian Serie A game.

[34] After more than two years from his last professional match and a total of three knee surgeries, Denílson was signed by Brazilian Série B club Botafogo-SP for the 2019 season.

[38] In August 2020 Denílson decided to come back to Europe, signing a one-year contract with the Maltese Premier League side Sliema Wanderers.

In November 2006, Denílson was called up to the Brazilian national side for a friendly match against Switzerland to replace his Arsenal teammate Gilberto Silva who pulled out for personal reasons.