Germany had been part of a three country battle with Portugal and Canada for two seats from a Western group of countries dominated by Europe.
Germany secured 128 votes in the first round, one more than the two-thirds majority required. Canada withdrew after an inconclusive second round, leaving victory to Portugal.
India, South Africa and Colombia all secured the two-year seats on the council in uncontested votes.
Five of the 15 nations on the Security Council are elected to two year terms each year. Britain, China, France, Russia and the United States are permanent members of the council who can veto any resolution.
The new countries will take the places of Japan, Austria, Turkey, Mexico and Uganda and give the Security Council a completely new political profile.
Germany, India and South Africa have all been pressing for a permanent role in a reformed Security Council. Brazil is also part of the campaign for change and it will go into a second year on the council as a non permanent member.
"We will discuss a reform of the UN, but not now, not today. It's necessary to change the structures to make the UN more effective," said German Foreign Minister Guido Westerwelle.
"The vote is a success for Germany. It shows that the world has trust in us. We will do everything to justify that trust," he added, setting out Germany's priorities as peace, security, climate protection, development, disarmament and nuclear non-proliferation.
"Germany is reliable - not only when it comes to its products but also when it comes to its foreign policy. The world knows it can rely on Germany," he told reporters.
India secured 187 votes and its UN ambassador, Hardeep Singh Puri, said his country was "humbled" by the score.
"It is a fact that many of the countries on the new council are also aspirants for permanent membership," said Puri, pointing to the presence of the emerging powers.
"Naturally all of us will try to use the time that we have during this two year tenure to also give our partners a sense of confidence, build trust, so that they are comfortable with our membership of the Security Council on an extended basis," the envoy told reporters.
Britain's ambassador to the UN Mark Lyall Grant acknowledged the changes that the new powers would bring to the new 2011 Security Council.
"All of them will bring their own unique advantages and make this a very strong Security Council," he said after the UN General Assembly vote.
Lyall Grant highlighted that Britain supported India, Japan, Germany and Brazil becoming permanent members of a changed council and increased African representation.
"It will be a mini-reflection of the sort of reformed Security Council that the UK would like to see," he told reporters.