Al-Ettifaq was founded in 1945 in Dammam, on Saudi Arabia's Eastern Province coastline, through the merger of three local clubs — Al-Taawoun, Al-Sha'ab, and Al-Shabab. The name chosen for the unified club, Al-Ettifaq, means "the agreement" in Arabic, a nod to the cooperative spirit that brought it into being. The club's colours eventually settled on green and red.
The club's first golden era arrived in the 1960s, when a generation of players led by defender-captain Khalil Al-Zayani began winning national silverware. Al-Ettifaq claimed the Crown Prince Cup in 1965 and the King's Cup in 1968, establishing themselves as a genuine force in Saudi football.
Their most celebrated period came in the 1980s. Under manager Al-Zayani, who had returned from playing to take the technical role, the club won the 1982–83 Saudi Premier League without a single defeat — a first in Saudi football history. They followed that with the 1984 Arab Club Champions Cup, becoming the first Saudi side to lift an international title, and the GCC Champions League title in the same decade. A second league championship came in 1986–87, alongside further continental honours including the 1988 Arab Club Champions Cup and 1988 Gulf Club Champions Cup.
As the club representing Dammam and the Eastern Province, Al-Ettifaq carry a distinct regional identity within Saudi football, often positioned as counterweights to the Riyadh and Jeddah giants. With 13 titles across domestic and regional competitions, they remain one of the most decorated clubs in the country.