[9][10] Among the signatories to the pledge are the European Commission, Council of Europe,[6] UNESCO,[6] and the governments of the following countries: The following online service providers, as part of the Global Internet Forum to Counter Terrorism (GIFCT) consortium,[6][15] also signed the pledge:[16] The United States, under (Republican) President Trump, declined to attend in 2019,[17] expressing concerns that US compliance with the agreement could create conflicts with free-speech protections in the country's Constitution; the United States however did support the summit's "overarching message" and "endorsed its overall goals".

[18][19] On 7 May 2021, White House press secretary Jen Psaki announced that the United States, under (Democratic) President Biden, would be joining the Christchurch Call and participate in a virtual summit on 14 May 2021.

[14][20] On 4 April 2023, New Zealand Prime Minister Chris Hipkins appointed Ardern as Special Envoy for the Christchurch Call.

"[23] Jillian York of the Electronic Frontier Foundation praised the Call for asking companies to provide greater transparency regarding its moderation practices, while expressing concerns about how terms such as "terrorism" and "violent extremism" are defined by various governments.

[25] Nick Gillespie of Reason criticized the summit, writing that "it should be deeply worrying to anyone who believes in free expression that governments and corporations are openly working together to decide what is and is not acceptable speech.