Dana had competed in the 1969 Irish National Song Contest — she was a resident of Northern Ireland and citizen of the United Kingdom but it was decided that year to have the Irish entry in Eurovision represent the island of Ireland in its entirety rather than just the Republic of Ireland.
Although in 1970 the Irish Eurovision entry reverted to representing the Republic of Ireland only, Dana had made such a favorable impression in the previous year's Irish National Song Contest - her performance of "Look Around" had come second - that the contest's producer Tom McGrath invited her to participate again singing "All Kinds of Everything," a composition by Derry Lindsay and Jackie Smith, two twenty-eight year old amateur songwriters who worked as compositors for a Dublin newspaper.
Dana's performance of "All Kinds of Everything" won the 1970 Irish National Song Contest and that 21 March - a Saturday - she performed the song at the Eurovision Song Contest held in Amsterdam. Dana was the twelfth and final performer on the night (following Germany's Katja Ebstein with "Wunder Gibt Es Immer Wieder"). Ireland chose not to send its own conductor to accompany Dana, so Dolf van der Linden, the renowned musical leader of the Dutch Metropole Orchestra, conducted his own orchestra for the Irish entry. Dana sang seated on a stool fashioned as a cylinder which left her feet suspended above the floor and caused her concern that she'd slide off. However Dana performed the song with the self-possession she had displayed at rehearsals, when the production team had her rise from her stool mid-performance to accommodate a set adjustment she continued singing regardless and earned a standing ovation from the orchestra.
"All Kinds of Everything" took first place in the contest with a total of 32 votes besting second place "Knock, Knock Who's There?" by Mary Hopkin by seven votes. 1970 had augured to be an off year for Eurovision with five nations boycotting the contest and an apparently predictable outcome with a victory by Hopkin or possibly Julio Iglesias (who in fact came in fourth with "Gwendolyne"). The surprise victory of "All Kinds of Everything" by the ingenuous Dana made 1970 one of the most memorable Eurovision contests.
"All Kinds of Everything" was the first Eurovision win for the Republic of Ireland; six subsequent victories have made that nation Eurovision's most successful entrant. "All Kinds of Everything" was also only the second song sung in English to win Eurovision outright (the first being Sandie Shaw's "Puppet on a String", with Lulu's "Boom Bang-a-Bang" sharing first place one year previously).
The entry was politically sensitive as Dana came from Derry in Northern Ireland, yet was representing Ireland, not the United Kingdom. At this time The Troubles in Northern Ireland were erupting, and some people found political symbolism of a Northern Irishwoman representing the Republic. On the other hand, the United Kingdom's entry the following year was sung by Clodagh Rodgers, who was also from Northern Ireland. Following her victory Dana returned to Derry and sang her victorious song to a crowd of cheering wellwishers from a balcony in the city.