He insists his entire focus will be on the arduous 2014 World Cup qualifying campaign from the very start.
Sabella succeeds Sergio Batista, whose contract was terminated by the Argentinian Football Association after the Albicelestes were eliminated in the Copa America quarter-finals on home soil.
The new boss, who assisted national coach Daniel Passarella between 1995 and 1998, said: "I'm honoured. To be the coach of Argentina is one of the biggest challenges in world football. It's an honour and a huge responsibility at the same time."
Sabella guided Estudiantes to the 2009 Copa Libertadores and the 2010 domestic opening title, and added: "I did not imagine I would have this chance so quickly, as I have coached Estudiantes for only two years. I have to thank the Estudiantes board, the players and my coaching staff who gave me this possibility too."
Sabella, who rescinded a contract to coach United Arab Emirates side Al-Jazira to take the Argentina post, will make his coaching debut on September 2 in a friendly against Venezuela in Kolkata, India.
Four days later, they will play Nigeria in Bangladesh.
"We must hand in the squad on August 18 and we'll pay attention to two things - firstly, India is a country you need a visa to arrive in and also you need vaccines, so the list of players could be longer than the ones who would finally travel," he commented.
In October, Argentina begin their 2014 World Cup qualifying campaign against Chile and Sabella wants to go step by step.
"This is a short, mid, long-term spell. We have a World Cup ahead, but firstly you have to qualify for it.
"If we talk about the World Cup, we have to think about the players growing up. In the qualifiers, you need experience and and a good temperament."
When asked about Lionel Messi being Argentina captain under his reign, Sabella said: "I will take some time to decide it."