Thomas Wilkie, 22, of Kent Road, was found guilty along with Shane Williams, 26, of Dragons Lane, Leicester, and Andrew Edge, 40, of Wellington Road South, Stockport at Birmingham Crown Court yesterday.
CCTV footage showed at the trial saw Wilkie kicking a hoarding and also kicking out at a police officer.
Judge Richard Bond warned the trio that he would consider an immediate jail sentence when he sentenced them later this year.
He told them: "Please don't think I am going to deal with you in another other way than an immediate custodial sentence.
"You all took part in this disorder and that crosses the custody thresh hold.
"At the forefront of my mind is an immediate custodial sentence."
Earlier in the trial, Mr David Bennett, prosecuting, said: ""He can be seen kicking some hoarding or fence line. When officers were deployed to protect the building site he was shouting and pointing aggressively towards the police.
"He was then on Broad Street, again gesturing towards officers, seen to kick out at officers, now with his face covered."
During police interview, Wilkie claimed he was in Birmingham to watch a football match and got caught up in the disorder.
Wilkie, Williams and Edge did not give evidence at the trial, which lasted two weeks.
CCTV images shown during the trial showed bottles, bricks and stones being thrown at the police, and also saw Williams, who was filming much of the demonstration on his mobile phone, pick up a bottle and throw it at police.
Edge was seen to push a Portaloo at police, which Dc Neil Weston, who had studied thousands of hours of footage from the rally, said had been used as a battering ram by protesters.
Edge told police in an interview that it had been pushed onto his head and he was trying to get it off.
A further man who had also been facing trial, Paul McKenzie, 47, of Braemar Road, Billingham, was found not guilty of violent disorder.
Wilkie and Williams were released on unconditional bail, while Edge was remanded in custody.
The 40-year-old chanted "EDL" as he was led out of the dock.
A total of 40 people pleaded guilty to charges relating to the disorder that took place during the demonstration in Birmingham on July 20 last year.
Arond 1,800 supporters of the far-right group met in Bar Risa in Broad Street on the morning of the demonstration, before marching down into Centenary Square, where they clashed with police officers.
A counter-protest was being staged in Chamberlain Square by the Muslim Defence League and Unite Against Fascism.
Sentencing is set to take place in December.