I'm usually cynical about role models – after all nobody is perfect. But then I saw a documentary, The Interrupters, showing in cinemas this week, and was utterly bowled over by Ameena Matthews.

Ameena is one of the few female members of the organisation CeaseFire, whose remit is to stop shootings using science and street outreach. In a city such as Chicago, riddled with crime, gang culture and some of the highest murder rates in the US, disputes between gangs often end in gun warfare, but Ameena and her colleagues use mediation to steer them away from violence.

Risking her life, putting herself in harm's way, you'd be forgiven for asking what the hell she is letting herself in for – but if there is such a thing as a calling in life then this is hers. Full of charm and charisma, her intelligence and gift of expression are all the defence she needs. Her ability to influence is in part due to her own involvement in gangs, drugs and violence at a young age. Her father, Jeff Fort, was a notorious Chicago gang leader and at one time she too was the enforcer of a drugs ring. This gives her an abundance of sympathy for individuals swallowed up in a spiral of criminality, but when speaking to young people she is keen to instil a sense of personal responsibility. In one scene Ameena discovers that Caprysha, a troubled young girl whom she has taken it upon herself to look after, has missed school. In unequivocal terms she rails at her: "Don't nobody have to kiss your ass for you to do what you need to do for you."

When Ameena arrives on screen you first notice the patterned headscarf wrapped tightly around her face – a subtle reminder of a faith, but one which is never offered as a cure-all. It's rare to see a woman speak with so much passion and conviction to a crowd of men, as she does spontaneously in the street at a vigil after a local murder.

There are other great Interrupters too, including the two other leading characters Cobe Williams and Eddie Bocanegra. But Ameena's magnetic presence is an example of a strong female leadership, which sets an example to young women – and men – within her community, and helps them to recognise self-worth while offering an alternative, less corrosive future. We would do well to recognise that in challenging circumstances, the responsibility to guide young people away from destructive attitudes lies not only with men but also that assertive, engaging women have a vital role to play.