The ceremony was conducted at a Bosnian mosque in Noble Park. The girl was 14 at the time and the man 34.
Omerdic pleaded not guilty to the charge but was convicted following a contested hearing before magistrate Phillip Goldberg.
He appeared before Melbourne Magistrates Court for sentencing on Wednesday.
Mr Goldberg said the only appropriate penalty was one of jail, and imposed a two-month sentence. But he ordered Omerdic be released immediately from custody and put on a two-year recognisance release order which is, in effect, a suspended jail term.
The order means Omerdic must be of good behaviour for two years, otherwise he will be jailed for two months and fined $2500.
The court heard that since his offending, Omerdic had been suspended from his position as an imam and a justice of the peace, and had his licence to conduct marriages cancelled.
Omerdic, formerly the imam of the Bosnian Islamic Society, had faced a maximum penalty of six months in jail.
Mr Goldberg said Omerdic’s offending was serious and a breach of the trust the community had placed in him, as he failed to protect a child. He had not shown any remorse.
But the magistrate took into account Omerdic’s loss of reputation, his unblemished record as a community leader, and his loss of income.
Prosecutors had called for Omerdic to be jailed immediately given his failings to protect the girl and because he knew a marriage was something only consenting adults could take part in.
Omerdic is believed to be the first imam convicted of the charge in Australia. He showed no emotion as the sentence was imposed or as he left court with a group of supporters.
Omerdic’s defence was he did not recognise the man and girl as true husband and wife, and that the marriage wasn’t formalised under Australian law.
But in reaching his verdict earlier this month, Mr Goldberg said the imam performed a ceremony that constituted a marriage, and that the evidence against him was compelling.
The man who was married to the girl – who cannot be named – earlier this year pleaded guilty to taking part in a forced marriage, an offence which carries a maximum penalty of seven years in jail.
He pleaded guilty after prosecutors withdrew a charge alleging he had sex with the girl after the ceremony.
The man is in custody and is due to appear before the County Court in September.
He could become the first person jailed in Australia for taking part in a forced marriage.
Rather than receive sympathy from the judge, the imam should be jailed then deported as should the Muslim mother of the girl – who sold her daughter for a $1,480 gold necklace.
More on Australia’s (Muslim) Child Bride Problem here.