NASHVILLE, Tenn. — Country record producer and songwriter Billy Sherrill, who helped create the smooth “countrypolitan” sound of the 1960s and 1970s, has died. He was 78.

Sherrill’s son-in-law, George Lale, said he died Tuesday in Nashville, Tennessee.

Sherrill’s production style incorporated over-dubbing, strings and background vocals into country music to encourage crossover success for artists like Tammy Wynette, George Jones and Charlie Rich. He produced hits such as “Stand By Your Man,” which he co-wrote with Wynette, “The Most Beautiful Girl,” “Behind Closed Doors,” and “He Stopped Loving Her Today.”

He was instrumental in signing Wynette, Barbara Mandrell and Janie Fricke to record deals. He also worked with Ronnie Milsap, Johnny Paycheck, Elvis Costello and Ray Charles.