After playing college basketball for the Duke Blue Devils, Deng was selected by the Phoenix Suns in the first round of the 2004 NBA draft with the seventh overall pick.

He developed an interest in football, admiring Faustino Asprilla of Newcastle United F.C.,[5] but also continued to play basketball, and was invited to join England's 15-and-under team in that sport.

[citation needed] Next, he led England to the finals of the European Junior National Tournament, where he averaged (34) points and earned another MVP award.

[citation needed] At age 14, Deng moved to the United States to play basketball at Blair Academy in New Jersey.

He was the 10th freshman in the Atlantic Coast Conference (ACC) history to lead all freshmen in scoring, rebounding, and field goal percentage.

Deng suffered a season-ending wrist injury late in his rookie season, but still made the NBA All-Rookie First Team and helped the resurgent Bulls return to the playoffs for the first time in seven years.

Deng also notably rarely committed fouls on defense (2.00 per game), despite the minutes he played and frequently being outsized in matchups against power forwards such as Kevin Garnett.

[citation needed] Deng scored 32 points against the Cleveland Cavaliers just three nights later, resolving concern that the wrist would be re-injured.

[16] After the agreement was announced, Bulls general manager John Paxson said in a statement "Signing Luol has always been a priority for this organization and we have always felt that he was a big part of our future.

[14] Deng played in a total of 70 games during the 2009–10 season, also increasing his scoring and rebounding to 17.6 and 7.3 respectively, helping the Bulls make the playoffs again.

[21] Deng finished the season averaging 17.4 points and 5.8 rebounds per game, being the third scorer for the Bulls behind Derrick Rose (25.0) and Carlos Boozer (17.5).

[22] During the first round of the 2011 playoffs against the Indiana Pacers, Deng averaged 18.6 points and 6.2 rebounds per game, being the second leading scorer of the team behind Derrick Rose.

On 31 March 2011, Eric Bressman of Dime magazine called Deng "the most underrated player" writing he was "never the face of the franchise but always the backbone".

Initially thought to be a minor injury, it was later revealed by a magnetic resonance imaging (MRI) that Deng tore the ligament in his left wrist.

[citation needed] On 9 February, Deng was selected as a reserve for the 2012 NBA All-Star Game, joining teammate Derrick Rose, who was voted in as a starter.

Deng made a buzzer-beating game winner on 24 March, off a tip-in basket to lift the Bulls 102–101 in overtime versus the Toronto Raptors.

Even without Derrick Rose, who was out for the whole year due to an ACL injury, the Bulls still tallied a 45–37 record, finishing fifth in the Eastern Conference and second in the Central Division.

Deng's representatives and Bulls executives had informal talks about extending his contract over the summer, but the team never made a formal offer.

[42] The Lakers signed the two-time All-Star along with Timofey Mozgov to big contracts in a bid to remain competitive after Kobe Bryant's recent retirement.

[43] However, in February 2017, Magic Johnson became the Lakers' president of basketball operations, and coach Luke Walton benched Deng to start rookie Brandon Ingram.

[44][43] He missed the final 22 games of the 2016–17 season after being shut down in March to give more playing time to the team's young players.

[43] He and head coach Walton mutually decided that it was better for him to stay in the locker room during games than to play meaningless minutes in garbage time.

[46] The move freed him to find playing time elsewhere, while the Lakers gained salary cap space to potentially offer a maximum contract to a free agent in 2019.

[44] On 10 September 2018, Deng signed with the Minnesota Timberwolves, reuniting him with Derrick Rose, Jimmy Butler, Taj Gibson, and head coach Tom Thibodeau.

[48] On 11 February 2019, Deng started in place of an ill Andrew Wiggins and scored 12 points in a 130–120 win against the Los Angeles Clippers.

In October 2006, Deng became a naturalised British citizen in a ceremony in Croydon and was called up to play in European competition for the Great Britain national team.

[52] He made his debut in a closed international test match against Georgia national team in Pau, France, on 9 August 2007, scoring 19 points.

[56] Deng has been credited with helping develop South Sudan's basketball presence and their rise on the international stage.

[60] On 24 November 2020, it was reported that Deng would coach the South Sudan national team in the FIBA AfroBasket 2021 qualifiers.

[72] Deng was appointed Officer of the Order of the British Empire (OBE) in the 2021 Birthday Honours for services to basketball.