The rocket launched at 6:51 pm (2151 GMT) from Europe's space port in Kourou, Guiana, Arianespace said.
The launch was delayed several times after the French territory in South America was hit by more than a month of disruptions following a general strike, which saw workers erecting barricades around the space centre.
The blockade was lifted on April 22, allowing for preparations to start afresh.
The first satellite, SGDC, separated from the rocket just over 28 minutes after lift-off and the second, KOREASAT-7, was placed in orbit a little more than 36 minutes from launch.
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The other satellite, KOREASAT-7 owned by South Korea's KTsat, will provide a range of video and data services over Korea, the Philippines, Southeast Asia, India and Indonesia.
The Kourou space centre has become a symbol of economic disparity in Guiana and a focus for anger, given that many locals have no electricity or running water and around one in four is jobless.
Workers downed tools against what they said was decades of under-investment in the French territory.
Guiana, home to some 250,000 people, has been administered as a French region since the end of the 18th century.
The labour action had delayed two other launches as well, and Arianespace chief executive officer Stephane Israel has estimated the total loss at about 500,000 euros ($546,000) per day for the company and its partners.