The 15-year-old boy, who cannot be named for legal reasons, uploaded his photo to a Grindr account used by a group of teens to attract a man they later extorted.

ACT Children's Court chief magistrate Lorraine Walker said the offence "preyed on the vulnerability of a particular section of the community" and described the scheme targeting gay men as "vicious".

She handed the boy a four-month term of imprisonment, suspended on condition he entered a good behaviour order, saying his offence was at a "lower level" compared to one of his accomplices.

The teenager, who pleaded guilty to a blackmail charge and other charges relating to supplying MDMA and Xanax, was part of a group that ambushed the victim who met them on January 26 believing he was going to see a man he'd spoken to on Grindr.

After they demanded $1000 and the man told the teens he only had $60 in his account, they walked with him to his house to find more money.

Chief Magistrate Walker said the boy suggested the man transfer $50 a week and later contacted him with bank details, before the victim contacted police about the extortion.

Prosecuting lawyer Sara Gul said the teen was motivated by greed and had "preyed upon the humiliation and vulnerability of the victim".

While he did not have anti-LGBTI views, his actions had targeted the gay community, she said.

Defence counsel Sarah Boxall said the teenager did not want to be associated with the anti-gay sentiment the extortion had involved and did not hold those attitudes.

The teenager's sentence comes after a 17-year-old Canberra teen involved in the blackmail ring last month was sentenced to 19 months' detention, to be suspended from mid-August upon him entering a 12-month good behaviour order.

Police charged four males, including the 17-year-old's older brother, in February after they cracked the extortion syndicate and linked it with the suicide in NSW of one of its victims.