The presenter described people involved in hunting and shooting as "the nasty brigade" in an article last year.
The corporation received two complaints from readers stating that Packham should not have expressed his personal opinion in a BBC magazine.
But the BBC Trust said the strapline had made clear the article was an opinion piece.
In a column in the October 2015 issue, the naturalist wrote that conservation groups were "hamstrung by outdated liaisons with the 'nasty brigade' and can't risk upsetting old friends" in the rural and shooting communities.
The Countryside Alliance complained Packham was breaking rules by using his position "to spread propaganda" and called for him to be sacked.
Packham responded by accusing his critics of trying to "neutralise" him and others who oppose grouse shooting.
In its report, published on Friday, the BBC Trust said Packham was a freelancer and therefore not a BBC employee, adding he was not "associated with news or public policy-related output".
It also noted that all parties named in the article had been given a right of reply prior to publication, and readers had the opportunity to respond in subsequent issues.
Both complainants have had letters published in the magazine in response to Packham's column.
The committee added the new editor would not have allowed the term "nasty brigade" to have been published.
In its summary, the BBC Trust said there had been no breach of the impartiality guidelines.
The committee also looked at whether Packham had breached the BBC's conflict of interest guidelines.
But the report stated: "It was clear that Mr Packham had been expressing his personal views as an individual, and that there was no implication that the charities and other causes he supported were endorsed by the BBC."
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The BBC Trust has said no action is required over comments Chris Packham made in BBC Wildlife Magazine.