Assala was born in Damascus, Syria to a middle class couple. Mostafa Nasri, Assala's father, was a revered Syrian composer and singer. Assala began her musical career by performing patriotic, religious, and children's songs when she was four years old. She sang the theme song "Qessas Al Sho'oub" (Arabic: قصص الشعوب), of the cartoon show, Hekayat Alamiyah (Arabic: حكايات عالمية). In 1986, Mostafa Nasri died after suffering from internal bleeding caused by a car accident. Aged 17 she helped care for her siblings, Reem, Amani, Ayman and Ayham with her mother.
Assala's commercial musical career debuted in 1991 with Law Ta'rafou (Arabic: لو تعرفو). The album had 4 songs in the oriental operatic tarab style. The album was an instant hit with heartbreaking songs like "Ya Sabra Yana" and "Samehtak Ketir". She quickly cemented her presence in a growing industry brimming with singers like Najwa Karam, Saber Rebaï, Angham, and Abdelmajeed Abdullah.
Assala has four children, two from her first marriage to Ayman Al Dahabi, and twins from her second marriage to a Palestinian-American director Tarek Al Eryan. She currently has custody of both their children, Sham and Khaled. She was pregnant with Tarek's child in early 2007, but suffered a miscarriage halfway through the pregnancy. Assala is a Sunni Muslim. She was granted Bahraini citizenship by Bahraini King Hamad bin Isa Al Khalifa a few days after she gave a performance in the operetta Love and Loyalty in celebration of Bahrain’s Independence Day. Assala holds two citizenships; Syrian (primary nationality) and Bahraini (second nationality) .
Sawaha Galbi (My Heart Has Done It) (2007), debuted at number 1, stayed for 4 weeks at number 1 beating Amr Diab's new album on Rotana's PEPSI Top 5 Albums
Nos Halah (Half State) (2008), debuted at #1 of Rotana's Top 5 albums on both Egypt and Lebanon, stayed in the charts the following week. In its third week it peaked back at number 1 at Egypt Top 5 albums charts. In the following weeks it peaked at number 2 on the Khaleeji, the making it the first album to be in the top 2 of all charts.