The deal to save Stormont's power-sharing Government was the "best possible agreement" for the people of Northern Ireland, Shaun Woodward said.
The Northern Ireland Secretary said all parties now had a responsibility to make the agreement to devolve policing and justice powers to Stormont work.
Mr Woodward criticised the Tories for establishing closer links with unionist parties, saying the Westminster Government had to be a "neutral broker" during sensitive negotiations in Northern Ireland.
Mr Woodward told Sky News' Sunday Live programme the deal was the latest significant step in the political process.
He said: "At Good Friday people decided to build on the land where they might one day have a house together.
"At St Andrews they actually had the house. But this is the decision to actually move in together, share power, live together, make it work and complete devolution.
"We should be very careful about being cynical.
"And we should also be very careful about one more thing: this is going to require all the parties in Northern Ireland to come on board."