Junior Hall, 50, was found guilty of raping the girl when she was 11, and was jailed for nine years at the Old Bailey.
The court was told the girl only summoned enough courage to go to police in 2010 when she was an adult.
A storyline in the BBC serial in 2001 featured physical and sexual abuse of the Little Mo character by her on-screen husband Trevor.
Mo confided to her sister Kat but said she did not want to go to court and repeat details to a courtroom full of strangers. Later in the series, Mo killed Trevor with an iron.
The girl believed she would not get any support and did not realise that she would be able to give evidence behind a screen.
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Mark Gadsden, prosecuting, said: ''At the time she felt the matter should be reported to police.
''She said she was influenced by a storyline in the programme EastEnders and didn't want to go through a court case as she didn't get any support.''
Hall, of Battersea, south London, denied the charge, claiming the attack never took place.
But Judge Timothy Pontius told him: ''She was completely defenceless when you assaulted her.
''She is very much to be congratulated, not only for her courage in reporting to police, but in the remarkable turnaround in her life.''
The judge said the girl had fallen into serious crime, but had chosen another path and achieved considerable academic achievement.
''She is a confident, articulate woman with strength of character,'' he added.