In 1996, a small group of people representing different denominations came together to see what they could do to reduce the growing number of people sleeping on the streets in their boroughs. Caroline Kennedy, one of the charity's founding members, recalls what brought the group together: 

All the churches were being approached at this time by rough sleepers who needed food and shelter, and most shop fronts on the Kings Road were occupied overnight.

The group called themselves "West London Churches Homeless Concern", and their first project was to research and produce an information card listing local resources to hand out to people sleeping on the streets.

Local homeless people told the group that what they could really use was a place to do laundry and take a shower. In response, the Chelsea Methodist Church opened a free laundry service in September 1998, thanks to a donation of washing machines from St Columba's church. 

The first night shelter network opened its doors in January 1999, thanks to seven churches agreeing to take turns hosting men and women overnight in their halls one night a week.

In 2000, the group gained charity status.

Every year, more churches joined the inter-denominational network, meaning more individuals experiencing homelessness could find a safe and warm environment during the coldest months of the year.

Over time it became clear that while the guests appreciated the daytime services and overnight shelters being offered, many wanted to end their period of homelessness. Many needed support to move on to more secure living. 

In response, the trustees supported the development of a casework service, which got under way during the 2007/2008 winter night shelter season. Demand for this service has grown, and our services struggle to keep up with demand.

In 2013, supporters joined the charity's first Sponsored Sleep Out in the Duke of York Square, raising enough money to run another shelter circuit during the 2nd half of the winter season. In subsequent years, the Sleep Out grew and was able to support the continued growth of the winter night shelters, helping open the night shelters and support services to more men and women than ever before.

In 2014, the trustees voted to change the name of the charity to something easier to remember and say. "Glass Door" was already being used by many of our guests as their nickname for the charity, and this name quickly became the front-runner. The charity officially became "Glass Door Homeless Charity", or Glass Door for short, on 21 May 2015.

In the winter of 2016-2017, a third circuit of night shelters opened in Wandsworth, joining the circuits in Kensington & Chelsea and Hammersmith & Fulham circuits.