The 20-year-old was the fastest qualifier in the morning, before winning both her quarter-final and semi-final races in dominant fashion.
She then carried that form into the final, easing well clear of Canadian Dominique Maltais in second, while France's Chloe Trespeuch claimed a bronze medal.
And it was Olympic heartbreak once more for America's Lindsey Jacobellis, who crashed when leading her semi-final and was forced to settle for seventh place.
The 28-year-old, who has eight X-Games gold medals in snowboard cross, crashed in 2006 while leading the final, before missing a gate in the 2010 semi-finals.
Samkova's medal was her country's first in the event and their first gold of the 2014 games, making Czech Republic the 19th country to have won gold in Sochi.
And that number already equals the record for a single Winter Olympic Games, set in Vancouver four years ago.
© Sportsbeat 2014
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