Eminem is the only other rapper to reach this milestone.
Kendrick Lamar hasn't slowed down one bit in the past decade. The man was putting out quality mixtape after quality mixtape that helped him build the dedicated following he had now and helped the release of his debut album, good kid m.A.A.d become a memorable moment in hip hop history. It was a great introduction to the kid from Compton who would later become one of the biggest stars on the planet. While he's released three other project since then (four if you include Black Panther: The Album), GKMC just hit a massive milestone on the charts.
Kendrick Lamar's debut album, good kid m.A.A.d city is the fourth hip hop album to ever hit 300 weeks on the Billboard 200. The rapper's 300 week run was nearly consecutive with the exception of one week where it fell off the chart in 2014. Eminem is the only other hip hop artist to have accomplished this. Three of Em's albums -- The Eminem Show (354), Curtain Call: The Hits (403) and Recovery (312) -- are the only other hip hop albums to tally 300 plus weeks on the Billboard Hot 100.
Overall, Kendrick Lamar's debut project is the 22nd album to ever spend more than 300 or more weeks on the chart. Pink Floyd's The Dark Side Of The Moon is in the lead with 937 weeks on the chart. Bob Marley and The Wailer's Legend: The Best Of... is the second album with the most weeks on the charts.