Police dashcam video of James Fields during a traffic stop in OH on May 25, 2017. Heyer was killed and 19 others were injured.
The charges include not only second-degree murder but three counts of malicious wounding and hit and run.
This weekend saw multiple incidents of violence at a counter protest to an alt-right/white nationalist rally in Charlottesville, VA, two of which resulted in fatalities.
Following a long silence on the initial far-right rally, US President Donald Trump spoke out to condemn the "violence on many sides" after the clashes on Saturday.
The authorities arrested Fields shortly thereafter. "Trump's not a white supremacist", Samantha Bloom told The Associated Press late Saturday.
Fields, seen here just before the incident wearing the unofficial uniform of a white supremacist group, was attending the "Unite The Right Rally" - a White Nationalist protest against plans to remove a Confederate statue from a public park.
The judge said that Fields will receive a preliminary hearing on August 25.
Fields joined the army in 2015, but remained on active duty for less than four months.
The 911 records show that Mr Fields's mother called a police agency in Kentucky several times in 2010 and 2011.