Helen Winter confessed to taking MDMA - the active ingredient in ecstasy pills - and being under its influence while with two clients of the children's charity around the 24 and 25 January previous year.
She also admitted testing positive for cocaine in a routine drugs test for Kids Company in 2014.
Dr Winter admitted that she was guilty of misconduct and that her fitness to practice is impaired, at the hearing at the Health and Care Professions Council (HCPS) in London today.
She also admitted to letting clients of the charity stay at her flat.
However, she denied offering MDMA to Client C or actually taking the class A drug in front of the youngster.
Kids Company, which, worked with children, young people and vulnerable adults who come from troubled backgrounds and have suffered drug addiction and abuse, collapsed in August amid allegations of financial mismanagement.
That investigation was led by Professor Stephen Briggs, who teaches Social Work at the University of East London and was a consultant for the charity at the time.
"Our attitude is to be firm, boundaried and compassionate".
Daniel Mansell, the presenting officer, told the hearing: 'In May 2014 concerns were raised in Kids Company about the registrant's drug use and inappropriate interaction with service users'.
He said Ms Winter went to the Hidden club in Vauxhall, south London, with her colleague Nicci Shall in January 2014 having purchased some MDMA on the way.
Shall told the tribunal that Winter offered the drug to her and a client, named only as "C", in the nightclub toilet.
Mr Mansell said: "On the 24th January 2014 Colleague A and the registrant went for a drink with other Kids Company employees".
She told the hearing: "I turned to my mentor again and mentioned about the staying over and he said I needed to go straight to Camila and not my local manager because she didn't think they were competent to deal with this".
Ms Shall told the hearing they were in the toilet when they saw the two young people known as Client C and Client D, both in their early 20s.
"At one point the registrant and Ms Shall and Client C went to the toilet and went to the cubicle".
"The registrant offered Client C some MDMA, Client C accepted and they took it".
The pair had met while working at the Urban Academy, a pupil referral unit run by Kids Company in Southwark, south London.
An internal investigation was carried out after she reported the matter to the charity's chief executive, Camilla Batmanghelidjh, but she raised concerns about the accuracy of the subsequent report.
In text messages from the day after the incident Ms Shall told Winter: "F***, f***, f***, I can't believe what we did".
She said: "I do not feel that the investigation report compiled by witness B accurately reflects my account of events".