But the former Spanish foreign minister says, for the moment, all his attention is focused on the conflict in the Balkans.
"My unique concern, to which I am dedicating all my energy, is to bring to an end the crisis in Kosovo," he said.
Mr Solana's term at Nato runs out in December, but with news of a possible breakthrough in the Kosovo crisis he could take up his new job sooner.
Late-night session
His appointment was made after a late-night session of the EU summit in Cologne.
Mr Solana had emerged for some time as the favourite in the race to become the EU's first high representative for foreign and security policy.
He has skilfully maintained the consensus among Nato's 19 members during the Kosovo crisis and is highly regarded in Washington.
Kosovo deal dispels doubts
But with Nato involved in its first war he had declined to confirm his candidacy, and some EU members had expressed doubts about the timing of his appointment.
Neutral countries in the Union were also believed to harbour some doubts.
They were brushed away by the unexpected news that a peace deal with Yugoslavia may be within reach, and the German Chancellor, Gerhard Schroeder, made the announcement just after midnight.
Tricky role
Mr Solana is now expected to play a key role in what has been a notoriously difficult area for the EU and to give the Union a higher profile on the world stage.
His deputy will be a respected diplomat, the French ambassador at the EU, Pierre de Boisseau, nephew of General Charles de Gaulle.
What remains unclear is whether Mr Solana will now serve out his term at Nato, which runs out in mid-December, and who will be his successor.
The German Defence Minister, Rudolf Scharping, was generally seen as a strong contender for the job but as Chancellor Schroeder told journalists, he decided he still had things to do in Germany.
Country profiles
Europe agrees military co-operation plan
(03 Jun 99 | Europe)
Serbia accepts peace plan
(03 Jun 99 | Europe)
Solana: Pushing for peace in Kosovo
(09 Feb 99 | World)
The BBC is not responsible for the content of external internet sites.
Violence greets Clinton visit
Russian forces pound Grozny
EU fraud: a billion dollar bill
Next steps for peace
Cardinal may face loan-shark charges
Vodafone takeover battle heats up
(From Business)
Trans-Turkish pipeline deal signed
French party seeks new leader
Jube tube debut
Athens riots for Clinton visit
UN envoy discusses Chechnya in Moscow
Solana new Western European Union chief
Moldova's PM-designate withdraws
Chechen government welcomes summit
In pictures: Clinton's violent welcome
Georgia protests over Russian 'attack'
UN chief: No Chechen 'catastrophe'
New arms control treaty for Europe
Mannesmann fights back
(From Business)
EU fraud -- a billion-dollar bill
New moves in Spain's terror scandal
EU allows labelling of British beef
UN seeks more security in Chechnya
Athens riots for Clinton visit
Russia's media war over Chechnya
Homeless suffer as quake toll rises
Analysis: East-West relations must shift