Barack Obama today celebrated today's decision and said that those who had campaigned over many years had finally been rewarded.
Speaking in the Rose Garden of the White House, Mr Obama said the 5-4 ruling was an important step in moving the US towards becoming a more equal country.
"Our nation was founded on a bedrock principle that we are all created equal. The project of each generation is to bridge the meaning of those founding words with the realities of changing times - a never-ending quest to ensure those words ring true for every single American," he said.
"Progress on this journey often comes in small increments. Sometimes two steps forward, one step back, compelled by the persistent effort of dedicated citizens. And then sometimes there are days like this, when that slow, steady effort is rewarded with justice that arrives like a thunderbolt."