Daniel Ward, 28, was sentenced on Friday at Birmingham Crown Court, where the prosecutor described him as being “so full on that even Nazi extremists took a step back”.
National Action became the first organisation to be banned by the government since World War Two in December 2016, following the murder of MP Jo Cox.
The court heard that he told fellow members he was “100 per cent committed” to fighting a war and had searched the internet for methods of building tear gas grenades and obtaining semi-automatic weapons.
Ward, of Bartley Green, Birmingham, admitted belonging to the proscribed group on 28 January.
Prosecutor Barnaby Jameson QC read aloud Ward’s initial email to National Action, which read: ”We are at war and it’s time for me to fight for my children’s future and the future of our people.
“... All I have to offer is my thirst for gratuitous violence!”
Further email correspondence revealed Ward was “impressed with National Action’s military channels”.
‘You seem almost militarised in your actions and sabotage,” he wrote.
Ward went on to praise Adolf Hitler, using strong antisemitic language. "Sorry if I’ve gone on, I just have nobody to discuss this with,” he said.
Ward then attended a meeting of the organisation in Dudley, where he was photographed performing a Nazi salute.
He did not heed the National Action ban, but did later part ways with the group, saying he was impatient for war and “had no interest in being involved with dreamers”.
Far-right protests are attracting the largest number of supporters since the 1930s, a report by the Commission for Countering Extremism revealed on Friday.
The study concluded that “the inability of politicians to manage Brexit competently and decisively” was undermining faith in the political system.
Four other defendants stood trial accused of the same offence in April, but the jury were unable to reach a verdict.
A re-trial has been set for January next year.
Ward will spend 10 years on licence in addition to his jail sentence.
Additional reporting by SWNS