Michael Avenatti, who represented the porn star Stormy Daniels in a lawsuit against President Trump, was found guilty of attempted extortion.
The lawyer was accused of trying to extort Nike for more than $ 20 million (£ 15 million).
He had threatened to divulge information that could be detrimental to the popular sports brand.
Avenatti emerged as Trump’s vocal critic two years ago when he began representing Daniels, and even suggested that he could run for president.
He could face up to 42 years in prison.