The youth service achieved this recognition through carrying out extensive self-assessment of its systems, practices and policies, and ensuring that excellent work with young people themselves was at the heart of it all.
Fiona Blacke, chief executive of the National Youth Agency, said: "There were many instances of good practice in Sefton's work that supported them in receiving this well-deserved recognition.
"The projects that target under-represented and marginalised groups are exemplary. Their commitment to staff development and training has not only enabled their own staff to progress, but also other partner organisations - a great advantage in terms of integrated service delivery."
Established in 2005 by the National Youth Agency as part of its work with the Local Government Association, the Quality Mark is a nationally recognised and externally validated process for assessing quality within organisations.
The standard is split into three themes - Policy and Strategy, People and Policy and Resources - again separated into 11 different operating standards, to cover all organisational building blocks.
More than 300 organisations have adopted the standards framework across the country since its introduction, with 23 of these having achieved the award.
Sefton Youth Service gained the status by ensuring that young people had the chance to influence youth services and access positive activities. Only by taking a holistic approach to understanding young people's issues were they able to achieve this award.
As an example of this, they invested in developing a sensory room with direct input from young people to help those with disabilities and introduced a communications channel called Board Maker to help young people with disabilities to take part in meetings, projects and everyday situations.
They also helped to increase young people's understanding of global issues by providing internationally focused opportunities.
David Hart, an officer in Sefton Youth Service, said: "Now that Sefton Youth Service has achieved the Quality Mark, it will be looking to maintain its current standards as well as taking the lead in new developments to further support enjoyment, development and the wellbeing of young people in Sefton."
