He was additionally part of Algeria's squad at the 2014 FIFA World Cup, where he finished as the team's joint top scorer with two goals.

[4] In May 2009, Slimani joined CR Belouizdad from JSM Chéraga for a transfer fee of 800,000 Algerian dinars,[5] signing a two-year contract.

[5] He started the 2013–14 season as a substitute, gaining a reputation as an impact player due to him scoring vital goals when coming off the bench.

[5] Due to the lack of form of Fredy Montero, however, Slimani became a starter and scored four goals in four matches in early March 2014 against Rio Ave, Braga, Vitória de Setúbal and in 1–0 over rivals Porto.

At the end of the season he finished third in the league, but in the Taça de Portugal he reached the final against Braga on 31 May 2015, slimani scored a goal helping Sporting turn around a two-goal deficit to eventually secure the cup following a penalty shootout 3–1.

[22] On 31 August 2016, the last day of the 2016–17 summer transfer window in England, Slimani joined Premier League champions Leicester City on a five-year contract.

[25] On 14 September, he made his debut for Leicester in the UEFA Champions League playing 62 minutes in a 3–0 victory over Club Brugge.

[27] On 27 September, Slimani scored the only goal in Leicester's 1–0 win against Porto in the Champions League group stage after a pass from Algerian national teammate Riyad Mahrez.

[29][30] After this goal, Slimani failed to score until matchday 11 of the Premier League against West Bromwich Albion from a pass from Mahrez, although Leicester lost 2–1.

[32] On matchday 15, Slimani helped the Foxes to win against Manchester City 4–2 after he presented two assists for goalscorers Jamie Vardy and Andy King.

[40][41] A thigh injury prevented him from making his debut for the club, which eventually happened exactly two months after signing, in a 1–0 win over Huddersfield Town, and he was involved in the build-up for the only goal of the game, scored by Ayoze Pérez.

[43] On 3 May, Slimani was given a three match ban for violent conduct after an off-the-ball incident with West Bromwich Albion's Craig Dawson, effectively ending his season with Newcastle.

[48] Despite scoring nine goals and seven assists in 18 league games before the Ligue 1 season was abruptly concluded due to the COVID-19 pandemic in May, Monaco chose not to give Slimani a permanent contract.

[54][55] He made his comeback on the pitch for Leões on 6 February 2022, coming off the bench in the 74th minute for Pedro Porro in a 2–0 league victory against Famalicão.

[63] In October 2009, Slimani was called up by Abdelhak Benchikha for the first time to the Algeria A' National Team for a week-long training camp in Algiers.

[64] In March 2010, Slimani was called up again, this time for a 2011 African Nations Championship qualifier against Libya as a replacement for his injured CR Belouizdad teammate Youcef Saïbi.

[70] Slimani was selected for Algeria's squad taking part in the 2013 Africa Cup of Nations, and played in all three group games in January.

[74] On 26 June, Slimani scored with a header in Algeria's 1–1 draw with Russia, helping the nation qualify for the knockout rounds of the World Cup for the first time ever after failing to do so previously in 1982, 1986 and 2010.

[77] Slimani was part of the Algeria team that won the 2019 Africa Cup of Nations,[78] scoring one goal in the tournament against Tanzania in the group stage.