LA Galaxy released a brief statement on Friday announcing that midfielder Katai and the team had "mutually agreed to part ways," after "strongly condemning" Tea Katai's posts when they became aware of them on Wednesday.
The statement continued: "The LA Galaxy stand with communities of colour, and especially the Black community, in the protests and fight against systemic racism, social inequality, bigotry and violence."
The 29-year-old Katai, who previously played for the Chicago Fire and signed with LA Galaxy in December, has apologised for his wife's social media postings.
He uploaded a lengthy statement onto his own Instagram page where he said her views "are not ones I share and are not tolerated in my family".
He added: "This is a mistake from my family and I take full responsibility."
Katai signed with the Galaxy as a free agent on December 31.
He moved to the MLS with Chicago in 2018 after a career in Europe, including time with Serbian giants Red Star Belgrade.
He had scored 18 goals in his first two seasons with the Fire, who signed him from Spanish outfit Alaves.
The MLS season has been on hold since March, when the coronavirus outbreak froze much of the professional sports calendar.