The former Lib Dem leader Sir Menzies Campbell said he was surprised to see Mr Salmond pictured with US secretary of state Hillary Clinton, and added: "This is no time for a novice."
He also recalled that Mr Salmond had called the 1999 Nato bombing of Serbia "unpardonable folly".
The criticism, made at the Scottish Liberal Democrats' conference in Perth, came during a session on international affairs in which Sir Menzies set out his views on the new US presidency, the Middle East, and Iraq.
Warning that a "cloudy" outlook is ahead in foreign affairs, he told the conference: "Against that background, I was somewhat surprised to see the enthusiasm which our First Minister rushed across the Atlantic to shake the hands of Hillary Clinton.
"To borrow some language from another time: in foreign affairs at the moment, this is no time for a novice," said Sir Menzies.
"The risk about novices in foreign affairs is that they commit mistakes.
"They behave in ways that are wholly inappropriate.
"Indeed the risk about novices is that they can be guilty of unpardonable folly – an expression you may remember from some time ago.
"These are difficult times, they require experience and sophistication –and its best to leave it to those who have both these qualities."
A spokesman for the First Minister hit back at Sir Menzies criticism of Mr Salmond, stating: "Menzies Campbell sounds like a pompous ass.
"He has never been in office in his life, and was so bad as Liberal leader that he wasn't even allowed to fight a general election.
"For the few dozen Liberal delegates who were there to hear him, this was less Ming the Merciless, more Ming the Meaningless – the Liberals are in such a bad way they can't even think of their own silly jibes anymore."
He said Mr Salmond had had an "excellent meeting" with Hillary Clinton and added: "Anyone would think Menzies Campbell would welcome that.
"His daft and negative remarks indicate exactly why the Liberals are in such a parlous state in Scotland, struggling to get into double figures in the polls."