Activists and police were spotted outside the Winter Garden, where the event was held, with one person seen sitting down in the venue’s doorway with a sign.
Security was also thorough inside the venue as bags and IDs were checked, although some activists in the crowd disrupted the event while Mrs Truss was speaking.
The audience members who caused the disruption were subsequently removed by security.
As Conservative members filled the Winter Garden, stickers, shirts and flyers were handed out.
Wealden MP Nus Ghani spoke at the event and voiced her support for Mrs Truss.
The Foreign Secretary said the country was facing ‘very, very difficult issues’.
Mrs Truss also spoke about protecting ‘single-sex spaces’ and fighting back against ‘identity politics’.
Deputy Prime Minister Dominic Raab also spoke at the event as he introduced Mr Sunak and discussed how Eastbourne had benefited from the former Chancellor of the Exchequer’s actions during the pandemic.
During his speech Mr Sunak spoke about family values and addressed the ‘significant’ challenges the country is facing.
Mr Sunak also spoke out against ‘lefty woke culture’.
During a question and answer session Mrs Truss said she wants to make sure universities are carrying out face-to-face lessons while also aiming to create a ‘British version of Silicon Valley’.
The Foreign Secretary even spoke about how she was part of the Liberal Democrat party when she was younger.
She said to the 1,000 Conservative members in attendance: “Some people have sex, drugs and rock and roll, I was in the Liberal Democrats.”
The Foreign Secretary also praised the ‘booming’ local wine industry and spoke about her aim to get more people back into offices.
She added: "I do think it is important that we get more people back into offices because we need to make sure our town centres and city centres thrive, but also you learn from other people when you are at work, when you are talking to each other.
"I think whilst it worked to some extent during Covid, I certainly got Zoom fatigue.”
While answering questions from members, Mr Sunak spoke to one Wealden resident who was concerned about planning applications in the district.
Mr Sunak said: “There shouldn’t be top-down targets imposed on places like Wealden that don’t take into account the very particular local circumstances. Particularly as you guys have got about 80 or 85 per cent of the land is AONB – it is an area of outstanding natural beauty –and the planning inspector needs to be told that that needs to be taken into account.”
During the question and answer session Mr Sunak said he was the person to appeal to swing voters.
The former Chancellor of the Exchequer also spoke about becoming carbon net zero by turning to innovation, ingenuity and entrepreneurship
The Conservatives’ next leader will be announced on September 5.