The footbridge was named in honour of the celebrated local playwright following a public vote in 2013.
Members of the Belfast and District Trades Union Council, other trade unionists and community groups were also in attendance and everyone contributed to a celebratory and carnival atmosphere.
First Minister Peter Robinson said: “It’s a shorter walk than the Peace Bridge in Londonderry, but it’s no less significant”.
Born in working class, Protestant east Belfast, Samuel Thompson (21 May 1916 – 15 February 1965) was a Northern Irish playwright, shipyard worker, lifelong trade unionist and Labour party candidate.
He is best known for his controversial plays, which exposed the folly of sectarianism and political corruption, such as ‘Over the Bridge’ and ‘Cemented with Love’.
The cycle and footbridge bridge will provide access to the ‘Connswater Community Greenway’ and links east Belfast with the burgeoning Titanic quarter and harbour estate.
“The bridge will be a fantastic resource for the community and businesses in the area and is a fitting memorial to a great trade union activist and voice for social reform,” said Paul Stewart, president of Prospect’s National Trust branch.
“Northern Ireland Prospect representatives were proud to be involved in the campaign to name the bridge after a much respected Belfast citizen and take part in the opening of a bridge that will prove to be a lasting legacy.”