Michael Adebolajo was “charismatic” and intelligence suggested that he had helped convert other inmates to Islam, Mr Justice Langstaff heard.
Detail of the influence Adebolajo wielded in jail has emerged after he took legal action against the Ministry of Justice.
Adebolajo claims that he was injured by prison officers during an incident in a cell and wants compensation.
Mr Justice Langstaff oversaw a preliminary hearing in the case at the High Court in London on Tuesday.
He said any trial was some distance off and made an order barring prison officers involved from being identified in media reports.
Fusilier Rigby, 25, died after being attacked near Woolwich Barracks in south-east London in May 2013.
Adebolajo, who is in his early 30s, and Michael Adebowale, who is in his mid-20s, were convicted of murder following a trial at the Old Bailey.
Adebolajo was given a whole-life jail term.
Adebowale was sentenced to life with a minimum term of 45 years.
Jurors heard that they mowed down Fusilier Rigby in a car before hacking him to death.
Mr Justice Langstaff said Adebolajo, who was not at Tuesday’s hearing, had complained about an incident in a cell while on remand in July 2013.
Lawyers representing the Ministry of Justice said prison officers likely to give evidence at any trial could be in danger if their names emerged in media reports.
They gave the judge detail of the influence Adebolajo had in prison.
“He forms relationships easily,” said the judge.
“He is charismatic.
“There is intelligence suggesting that he has had some influence on the conversion to Islam of some individuals.”
The judge added: “There is a large group of people who look up to Adebolajo.”
Mr Justice Langstaff said the incident at the centre of Adebolajo’s claim had occurred while he was awaiting trial.
Five prison officers had been escorting Adebolajo. Physical force had been used to restrain him.
He had been held by the head and an arm and had lost two front teeth.
The judge said the use of physical force by prison officers had to be justified.
Ministry of Justice lawyers told the judge that prison officers were “deeply unhappy” about being involved in legal proceedings.
Mr Justice Langstaff said Adebolajo had not been given legal aid to pay for lawyers to represent him.
He said Adebolajo might have to represent himself at any trial and suggested that it would be in the interests of justice if public funding could be given.
“If and when this case comes to trial it will be a great pity to justice, and in particular the presentation of the claimant’s case, if some means were not found to ensure he had professional help,” said the judge.
“If that could be done by public funds all the better.”
Adebolajo had screamed ”Allahu akbar” as he and Adebowale were sentenced by a judge at the Old Bailey in February 2014 after being convicted of Fusilier Rigby’s murder.
The two British-born extremists, who were dressed in Islamic robes, erupted with rage as Mr Justice Sweeney told them that they had been radicalised and betrayed their religion.
Both were pinned to the ground and bundled out of court by prison officers.
Mr Justice Sweeney said: “You each converted to Islam some years ago. Thereafter you were radicalised and each became an extremist, espousing a cause and views which, as has been said elsewhere, are a betrayal of Islam and of the peaceful Muslim communities who give so much to our country.”
He added: “You decided between you, and in order to advance your extremist cause, to murder a soldier in public in broad daylight and to do so in a way that would generate maximum media coverage.”