He endorsed Mr Biden in an op-ed published by the Wall Street Journal.
Mr McRaven - who oversaw Operation Neptune Spear, during which Osama Bin Laden was killed - said that though many of his social views do not fully align with those of the Democratic party, he believes Mr Biden is a more capable and respectable leader than Donald Trump.
“Truth be told, I am a pro-life, pro-Second Amendment, small-government, strong-defense and a national-anthem-standing conservative,” he wrote. "But, I also believe that black lives matter, that the Dreamers deserve a path to citizenship, that diversity and inclusion are essential to our national success, that education is the great equalizer, that climate change is real and that the First Amendment is the cornerstone of our democracy. Most important, I believe that America must lead in the world with courage, conviction and a sense of honor and humility."
Mr McRaven never directly attacks Mr Trump in the letter, but he does criticise the country's leadership. He argues that the world's view of the US has been tarnished in recent years and that other countries no longer look to it for leadership.
“They have seen us tear up our treaties, leave our allies on the battlefield and cozy up to despots and dictators,“ Mr McRaven wrote. “They have seen our incompetence in handling the pandemic and the wildfires. They have seen us struggle with social injustice.”
Mr Biden was endorsed by nearly 500 US generals, admirals and intelligence officials in September, including 22 retired 4-star officers.
Mr McRaven’s op-ed is not his first public criticism of Mr Trump's leadership.
In 2018, Mr McRaven called Mr Trump's attacks on the press "the greatest threat to democracy in our lifetime," and later claimed that the US was under attack "from within."
Despite his criticisms, Mr McRaven may share some of the fault for the way the US is viewed globally; in 2008 he took over as the head of the US Joint Special Operations Command, a collection of highly trained special forces units from across the US military that essentially served as a paramilitary operating at the behest of the White House and largely under Congressional radar. The command was established under former Vice President Dick Cheney and Secretary of Defense Donald Rumsfeld.
He oversaw operations - ordered by President George W Bush - that sent special forces units in to Pakistan, without the country's knowledge, to hunt suspected terror suspects and engage in extrajudicial killings.