Christopher Steele, who runs London-based Orbis Business Intelligence, said he was returning to work and thanked people for their support.
Speaking outside his firm’s offices in Belgravia, he told the Press Association: “I’m really pleased to be back here working again at the Orbis’s offices in London today.
“I’m now going to be focusing my efforts on supporting the broader interests of our company here.
“I’d like to say a warm thank you to everyone who sent me kind messages and support over the last few weeks.
“Just to add, I won’t be making any further statements or comments at this time.”
The company said in a statement that it remains committed to the “secure provision” of services to clients.
“Orbis Business Intelligence has an established track record of providing strategic intelligence, forensic investigation and risk consulting services to a broad client base,” it said.
“The nature of our business, and our high standards of professionalism, dictate that we would not disclose to the public information on any specific aspects of our work. We remain fully committed to the secure provision of our services to our clients and partners worldwide.
“We would like to take this opportunity to express our gratitude for the generous support we have received from clients and colleagues over recent weeks.”
A former MI6 agent, Mr Steele was forced into hiding in January when he was named in connection with the report.
The dossier contained politically explosive claims that Russia was in possession of compromising information - known in Moscow as “Kompromat” - on Mr Trump, which could be used to blackmail or exert pressure on the new president.
It detailed allegations that the Trump team had multiple contacts with Russian officials during the election campaign, and that the billionaire tycoon had been cultivated by Moscow over a number of years as a possible presidential candidate, with the aim of encouraging splits within the West.
Among its more lurid allegations was a claim that the Russians held evidence of Mr Trump hiring prostitutes during a visit to Moscow to urinate on a hotel bed which he believed to have previously been slept in by Barack and Michelle Obama.
Mr Trump denounced the document as “fake news”, and its veracity has been widely questioned, with Vladimir Putin himself saying it contained “obvious fabrications”.
Mr Steele, who read from a prepared statement, did not wish to answer any further questions about the claims.