The SNP leader seemed to deliberately raise the flag behind the Prime Minister's head in the Royal Box on Centre Court yesterday so it would be in the television shot.
Supporters of the Union have accused him of "photobombing" Mr Cameron and breaking All England Club rules - which state that large banners and flags cannot be used around the courts.
But Salmond told the BBC Radio 4 Today programme that he had "no idea" what the seating plans were, and the Wimbledon authorities had not minded his actions "in the slightest".
"I think it (is) a rule more observed in the breaking than the observation," he added.
Stressing that the incident happened after the match had finished, Mr Salmond pointed out that, while Britain had waited 77 years, no Scot had won the tournament since Harold Mahoney in 1896.
"It is not something that happens very often so I think a few Saltires hoisted over Wimbledon does not do any harm at all," he said. "I had no idea what the seating arrangements were - that is absolutely the case."
He said the flag had been in his wife Moira's handbag.
Asked whether Murray's achievement had been a triumph for Britain, he replied: "Absolutely, and for tennis fans everywhere. Let everyone enjoy the triumph. But you will allow us just the little sneaky thing of the first Scot since 1896. Let us wave our Saltires."
Mr Salmond insisted his actions had not upset the All England Club.
He told BBC Radio Scotland's Good Morning Scotland programme: "The All England Club were ladies and gentlemen about it, they are nice people."
The First Minister added: "The Saltire is our national flag, Andy is a fantastic, magnificent Scottish sportsman, anybody has got the right to wave the national flag, it's a great way to celebrate this amazing triumph."
Murray's victory may be the "pinnacle of Scottish sporting triumph", the First Minister said.
"It's right up there, it's up there with Chris Hoy, or Celtic and the European Cup," he stated.
"It's an amazing victory. Paul Lawrie, Sandy Lyle in the Open. It's probably the pinnacle. He says it's the pinnacle of tennis, this might be the pinnacle of Scottish sporting triumph.
"It's an absolutely astonishing triumph."
He hailed the tennis star as the "king of Scotland" as he suggested a reception for him could be held in Stirling Castle, near Dunblane, where Murray grew up.
When asked what plans there were to honour the sportsman, Mr Salmond said: "He's already got the freedom of Stirling, I was thinking of a reception in Stirling Castle, which has got a nice sort of home town ring to it with Dunblane, something like that.
"But Andy is king of Scotland, he can have anything he likes."