The divorce filing and court records used only initials to refer to the pair, with Todd Mitchell Palin listed as TMP and Sarah Louise Palin only identified as SLP, according to the US media.
The Palins, both 55, married in 1988 and have five children together.
Friday's filing included a child custody jurisdiction affidavit for the family's youngest child, who is 11. Reports say that the couple has sought joint custody.
Sarah Palin was Governor of Alaska from 2006 till 2009 and shot to prominence when she became Republican Senator John McCain's running mate in the 2008 presidential election, which he lost to Barack Obama.
Since then, she appeared in several reality TV shows along with Todd Palin -- a commercial fisherman and oil field worker. The Palins also faced notable attention, at times unflattering, in past several years.
Bristol Palin, who was pregnant during her mother's vice presidential campaign when she was 17, was featured in MTV's "Teen Mom OG" in 2018. But she announced her exit from the show in April, saying, "It took away my peace".
In 2018, the Palins' oldest child -- 30-year-old Track Palin -- was arrested on domestic violence charges, to which he pleaded not guilty.
He had earlier pleaded guilty to criminal trespassing in a dwelling after being accused of breaking into his parents' home and assaulting Todd Palin.
Sarah Palin also has a lucrative career as a public speaker and published two bestselling books. She championed the grassroots Republican Tea Party movement and was also a vocal supporter of US President Donald Trump during his 2016 presidential campaign.