Having started his professional career with Colombian side Deportivo Cali, Muriel joined Udinese. His first two seasons at the club saw him loaned out to Granada and Lecce respectively before returning to the club in 2012, during which year he won the Serie A Best Young Revelation award along with Stephan El Shaarawy. After scoring 15 league goals in 57 appearances, Muriel joined fellow Serie A side Sampdoria in January 2015. He spent two-and-a-half seasons with the club, scoring 21 goals in 79 league appearances before joining current club Sevilla in 2017.
Muriel is currently a Colombian international having represented his nation at a full international level since 2012. He made his senior debut in June 2012, in a World Cup qualifying match against Ecuador and scored his first goal the following year, netting against Guatemala.
Having spent his formative years with Atlético Junior, Muriel joined Colombian Primera A side Deportivo Cali in January 2012. He made his debut against Envigado FC on 12 July 2009 in what would be his only appearance for the year before scoring scoring nine goals in 10 appearances the following season. Muriel's early form for Deportivo, which included a hat-trick against Once Caldas in his third match, earned him the nickname "the Colombian Ronaldo", in comparison to former Brazil striker Ronaldo, and midway through the season he was signed by Italian Serie A side Udinese.
Udinese officially completed the signing of Muriel, who was 19-years-old at the time, on 30 May 2010 for a reported fee of €1.5m. In terms of the transfer agreement, Udinese obtained 70% of Muriel's playing rights with the remaining 30% being retained by Deportivo. Shortly after his arrive in Udine, however, he was loaned to Segunda División side Granada.
Muriel completed his loan move to Granada on 12 July 2010. The club achieved promotion to La Liga for the first time in 35 years but it was an unsuccessful spell for Muriel, as he made only seven appearances for the season and failed to score.
Upon the expiration of his loan with Granada, Muriel was loaned out again for the following season to fellow Serie A side, Lecce. He made his debut for the club on 27 October 2011, coming on as a second-half substitute for Daniele Corvia in a 2–0 loss to Palermo. On his first start for the club the following month, against Cesena Muriel was sent off for two bookable offences. Lecce hung on to claim a 1–0 victory, however, thanks to a goal from fellow countryman and Udinese-loanee, Juan Cuadrado. He improved to end the campaign with a return of seven goals in 29 appearances, though his efforts were not enough to prevent Lecce from being relegated to Serie B. His form during the course of the season caught the attention of A.C. Milan and Internazionale, with both clubs making official offers to sign him, but Muriel confirmed that he would be returning to Udinese.
Muriel's poor physical condition upon his return to Udinese drew the ire of Francesco Guidolin, with the club manager insiting that he needed to lose five pounds, despite the player scoring four goals against Arta Cedarchis in a pre-season friendly. He was able to get in shape for the start of the season and made his debut in a 2–1 defeat against Fiorentina on 25 August 2012, providing the assist to Maicosuel for the opening goal. He signed a contract extension the following month, signing an improved five-year deal with the club. In January 2012, Muriel was awarded the Serie A Best Young Revelation award alongside Milan's Stephan El Shaarawy in recognition of his form with Lecce and Udinese the previous year. By the conclusion of the season, he had contributed a return of 11 goals in 22 Serie A appearances, despite having missed nearly four months of football because of a hairline fracture of his left femur.
The following season, in the qualifying playoff rounds of the 2013–14 UEFA Europa League, Muriel scored his first ever European goals, netting twice in a 3–1 victory over Široki Brijeg and in his first league match of the season, scored against reigning Coppa Italia champions, Lazio in a 2–1 loss. His form declined however, as he struggled with weight and injury issues, and over the course of the next season-and-a-half he scored only four goals in 35 league appearances, including a spell of zero goals in 11 matches from the start of the 2014–15 Serie A season. He ultimately amassed 15 goals in 57 appearances for the club, before leaving to join Sampdoria in 2015.
In spite of his struggles with Udinese, Sampdoria completed the double loan signings of Muriel and teammate Andrea Coda on 22 January 2015, with an obligation to purchase both players at the end of the season for a combined sum of €12m. In terms of the agreement, Muriel signed a contract with Sampdoria until 30 June 2019. He scored four times in 16 appearances during his loan spell before completing a permanent transfer at the end of the season. In his final campaign with the club he recorded a career best return of 11 league goals and five assists, which prompted Sevilla to break their club record to sign him at the end of the season.
On 11 July 2017, La Liga side Sevilla announced the signing of Muriel for a reported club-record fee €20m, with potential add-ons. He made his debut on 19 August, starting in a 1–1 draw with Espanyol.
Between 2009 and 2011, Muriel represented Colombia at U20 level and featured for the nation at the 2011 FIFA U-20 World Cup for which Colombia were the host nation. On 6 August 2011, having previously scored twice against France, he scored the only goal of the match as Colombia beat Korea Republic 1–0 to progress from the group stages with a perfect record. Muriel ultimately scored four goals for the tournament before Colombia were knocked out by Mexico in the quarter-finals.
Muriel was called up to the senior side for the first time in 2012 by new manager José Pékerman and made his debut in a 1–0 World Cup qualifier loss to Ecuador on 10 June. He scored his first goal the following year, scoring in a friendly against Guatemala on 6 February 2013. The following year, he was one of seven players cut from Colombia's extended squad for the 2014 FIFA World Cup in Brazil. He was a member of Colombia's squad for the 2015 Copa América but was overlooked for the Copa América Centenario the following year.As of matches played on 27 August 2017.
1 Includes Coppa Italia and Copa del Rey matches.As of matches played on 27 August 2017.
Scores and results list Colombia's goal tally first.
2 Includes UEFA Europa League matches.
Muriel has been praised often during his time in Italy, which led him to win the award for best young player in the Serie A league in 2012. Many figures in Italy such as fellow Udinese teammate Antonio Di Natale, praised him for his technique on the ball and potential.
Muriel stated that his comparison to Brazilian legend Ronaldo by his playing style, is likely because he was a main supporter of Ronaldo during his time in Inter Milan. he went on to say that he supported Inter Milan because Ronaldo was playing for them at the time. Coincidentally, he also stated that he also suffers weight issues (like Ronaldo during his time) and had to lose five kilos at one point. This meant that he had to be consistent with fitness, which explained his similar style to the Brazilian legend and high quality in terms of athletic stature.Serie A Best Young Revelation: 2012