Born in Souk Ahras, Makhloufi made his international debut at the 2007 IAAF World Cross Country Championships, where he finished 82nd in the 8 km junior race. He began competing at the senior level in 2009 and at the 2009 Mediterranean Games he placed fourth in the 1500 metres. An appearance at the Golden Gala meeting followed soon after and he ran a personal best of 3:34.34 minutes. He won his first national title that year and represented his country at the 2009 World Championships in Athletics, where he was a semi-finalist. In 2010 he improved his best to 3:32.94 minutes at the Herculis meeting and ranked among the top twenty that year. He reached the 1500 m final at the 2010 African Championships in Athletics, but failed to finish. Makhloufi's fastest run of 2011 came at a national meeting in Algiers and he competed twice on the 2011 Diamond League circuit. After taking his second Algerian 1500 m title, he was again selected for the World Championships team and again reached the semi-final stage. It was at the 2011 All-Africa Games that he made his international breakthrough. He won the 1500 m bronze medal behind Kenyan opposition, then defeated the much more favoured Boaz Kiplagat Lalang in the 800 metres final to take his first continental gold medal. Following this success he began to compete more frequently in the 800 m in the 2012 season. His first 1500 m race of the season was a runner-up finish at the Rabat Meeting and he improved his 800 m best to 1:44.88 minutes in Stockholm. Building upon his previous African title, a tactical mistake by the leading Kenyan runners helped Makhloufi win the 800 m title at the 2012 African Championships in Athletics, setting a personal best of 1:43.88 minutes in the process. On 20 July he set a new personal best at the 1500 m at Herculis meeting in Monaco with a time 3:30.80. He achieved the qualifying standard for the 1500 m and 800 m and was entered in both races at the 2012 Summer Olympics. He reached the 1500 m final after winning his heat and semi-final. The Algerian Olympic Association had failed to withdraw him from the 800 m event, which he no longer wished to compete in, and he was forced to enter the race. Makhloufi slowed and dropped out in the early stages of his 800 m – a performance that led to him being disqualified from the Games as the IAAF referee "considered that he had not provided a bona fide effort". However, he was re-instated after producing an independent medical certificate showing that an ailment had hampered his efforts. The following day, Makhloufi won the 1500 m Olympic final with a time of 3:34.08 minutes. This performance surprised critics given his previous medical statement and the quality of the field. Makhloufi explained that his improvements stemmed from a change of coach and his intensive training that year. On 1 July 2015, he won the European Athletics Classic meet 1000m in Tomblaine, France in a new Algerian record of 2:13.08. On 15 August 2016, he set a new personal best and Algerian record in the 800m final at the Olympic Games in Rio with a time of 1:42:61 finishing second behind David Rudisha from Kenya.
