"GNX," the performer's sixth studio album, appeared on streaming services without fanfare at midday on the US East Coast (1700 GMT).
The offering from the 37-year-old comes at the end of a year that has seen his music fueled by a feud with Drake, a spat that produced some of the year's biggest hits.
One of them, Lamar's "Not Like Us," grabbed the top spot on Billboard's Hot 100 chart and garnered him a number of Grammy nominations for next year's gala.
"GNX" is the first album from Lamar since his mega-selling "Mr. Morale & the Big Steppers" in 2022, which itself came after a five-year wait.
Friday's release is timely for an artist who will headline the Super Bowl halftime show in February, a coveted showcase that takes place in the middle of the NFL season finale, which is routinely watched by around a third of Americans.
