Kluwe and his attorney announced the legal action at a Tuesday morning press conference in Minneapolis hours after he revealed the team's suppression of the six-month investigation.
The Vikings retained two attorneys to investigate Kluwe's allegations, which he detailed in a January essay for Deadspin.
Kluwe alleged that his vocal support for same-sex marriage led to his abrupt release from the team in 2013. Moreover, he said that Minnesota's special teams coach Mike Priefer frequently made homophobic remarks.
Priefer, who remains with the Vikings, strongly denied the allegations.
The team said in a statement Tuesday that Kluwe was never promised that he would get to see the report.
An unnamed team source told television station KSTP that the Vikings opted against releasing the report because it was "damaging and embarrassing" to the franchise.