Country music has lost one of its all-time hitmakers — Don Schlitz, the mastermind behind “The Gambler,” has died at 73.

Schlitz died Thursday at a Nashville hospital after a sudden illness … and the loss is hitting the industry hard. A member of the Grand Ole Opry and the Country Music Hall of Fame, he was a legend in the songwriting game.

His catalog reads like a greatest hits playlist. Schlitz wrote smashes for Kenny Rogers (“The Gambler,” “The Greatest”), Randy Travis (“On the Other Hand,” “Forever and Ever, Amen”), The Judds, The Nitty Gritty Dirt Band, Tanya Tucker and Mary Chapin Carpenter … just to name a few.

He even helped reunite Rogers with Dolly Parton … penning “You Can’t Make Old Friends” — their first duet since “Islands in the Stream.”

Of course, “The Gambler” remains his crown jewel — winning a Grammy for Best Country Song and CMA Song of the Year and becoming one of the most iconic tracks in country history.

The accolades didn’t stop there … Schlitz racked up four straight ASCAP Country Songwriter of the Year wins, multiple CMA and ACM honors and two Grammys. He was inducted into the Nashville Songwriters Hall of Fame back in 1993.

Beyond the hits, those who knew him are remembering the man behind the music. Carpenter shared a heartfelt tribute, writing … “Remembering this beautiful person today … his kindness, humanity, and compassion for friends, strangers … no one stayed a stranger for long.”

Schlitz is survived by his wife, Stacey, his children, grandkids, and siblings.