Hamdallah started his professional career when he played for Olympique Safi of Morocco's top league. On 14 February 2013, it was confirmed that Hamdallah had joined Tippeliga club Aalesund, the transfer fee was the highest Aalesunds FK has paid for a player ever. Hamdallah made his debut on 1 April 2013 as a substitute in the 0–1 away win of Sandnes Ulf and then scored his first goal for the club, in a 2–0 win over Sarpsborg 08 on 14 April 2013. Then on 13 May 2013, Hamdallah scored his first hat-trick for Aalesund in a 7–1 win over Lillestrøm SK, which he helped the club into second place after nine games. After scoring ten goals so far this season, Hamadallah scored his second hat-trick of the season, in a 3–1 win over Viking on 25 October 2013. In his first season, Hamdallah had a successful season with the club, scoring fifteen times in twenty-seven appearance and was included in the Team of the Year. Also, it left Hamdallah as the club's top scorer, though he was the second top-scorer behind Frode Johnsen. In February 2014, Hamdallah joined Chinese Super League side Guangzhou R&F. His departure from Aalesunds left the club very affected, due to his goal-scoring form, something the club now struggle since Hamdallah left Norway for China. After making two appearance at the start of the season, Hamdallah scored his first hat-trick of the season, in a 3–1 win over Shanghai Shenxin on 22 March 2014. In the next game against Hangzhou Greentown, he scored another hat-trick in a 6–2 win. He scored again in the next match against Henan Jianye, which he scored twice in a 4–0 win. After a week out over a leg injury, Hamdallah scored the winning goal, in a 1–0 win over against reigning champion, Guangzhou Evergrande. In his first season at Guangzhou R&F, Hamdallah made twenty-two appearance and scoring twenty-two times. Despite making a good start in the first four matches and scoring three times against Hangzhou Greentown, Shanghai SIPG and Guizhou Renhe. Hamdallah also scored in the group-stage of AFC Champions League match against Gamba Osaka. On 24 July 2015, Hamdallah joined El Jaish in the Qatar Stars League. Hamdallah played for Morocco U-23 where he scored important goals during the African qualifiers to the 2011 CAF U-23 Championship. In December 2012, Rachid Taoussi, Morocco's National Team coach, called him up to be part of the 24 players to be part of the Moroccan squad going to the 2013 AFCON in South Africa. Hamdallah made his debut for Morocco in a friendly against Burkina Faso in February 2012.