It was the third time that the court has removed an elected Thai leader with ties to former Prime Minister Thaksin Shinawatra, Yingluck's billionaire brother, who was expelled from power in a bloodless 2006 coup.
Critics have accused Thaksin of using Yingluck and other former prime ministers as his proxy, while he pulls the political strings from exile in Dubai.
The court's decision is the latest incident to plunge the country into disarray during a long-running power struggle between the traditional political elite and their middle- and upper-class base in the capital Bangkok and Thaksin's so-called Red Shirt supporters - mostly rural villagers living in impoverished areas in the country's north and northeast.
The court ruling "prolongs the vicious political divisions that are tearing Thailand apart", Rajiv Biswas, an economist and Asia-Pacific analyst for IHS Global, told Al Jazeera.
"The political standoff looks set to continue, with extremely negative implications for the economy."
The Red Shirts and their political organisation - the United Front for Democracy Against Dictatorship - could mobilise in large numbers to protest against against the court's decision, as they did in 2010 when they took over Bangkok's central business district for months, before the military launched a bloody crackdown.
The Shinawatra clan enjoys the support of the majority of Thais, who have overwhelmingly voted their political parties into power in every election since 2001.
A new vote is expected in late July - one that would in all likelihood return a government made up of Thaksin allies.
Speaking to Al Jazeera from Bangkok, Thitinan Pongsudhirak, director of the Institute of Security and International Studies at Chulalongkorn University, said it was crucial for an election to take place.
"The only way out and the ultimate way forward in this flawed electoral democracy is still to stick to the popular mandate as the least problematic of all options," he said.
An unelected outcome is likely to bring more tumult and turmoil."
Thursday's ruling was not the first time the Constitutional Court had waded into Thailand's murky political waters.