Meyer-Landrut's song 'Satellite' beat 24 other acts from across Europe to romp home in first place.
Lena's 246 points were enough to secure Germany only its second-ever Eurovision title ahead of second-placed Turkish act maNga with 170 points, and Ovi & Paula Seling of Romania in third (162 points).
Pre-contest favourites Azerbaijan managed only fifth position, while this year's ranking was propped up by the United Kingdom with a measly 10 points.
This year's competition – which saw 39 countries take part in initial heats before being whittled down to 25 for Saturday's final - took place against a backdrop of political division and resentment in Europe, with voters in large eurozone member states like Germany growing increasingly bitter at having to bail out debt-ridden Greece.
Indeed, public anger over Angela Merkel's decision to aid Athens played a decisive role in her centre-right coalition's defeat in a key state vote earlier this month, which deprived the German chancellor of her majority in parliament's upper house (EurActiv 10/05/10).
"Lena has, in her own special way, won over not only Germany but the whole of Europe," Lutz Marmov, director of German public broadcaster NDR, is quoted by the International Herald Tribune as saying.
The economic downturn even affected this year's Eurovision, with some countries – including regulars Hungary, Andorra, the Czech Republic and Montenegro - having to pull out of the event after the cost of participating proved prohibitive.
Christian Wulff, leader of Lower Saxony, was on hand in Lena's hometown of Hanover to give the teenager the red carpet treatment on her return, whisking her to the city's main square where she was feted by cheering crowds.
Her victory was watched by 18,000 spectators in Oslo's Telenor Arena and an audience of millions watching at home on TV and online.