Billy DeMars, the hitting coach for the 1980 world champion Phillies and the team’s oldest living alumnus, died Thursday morning. He was 95.

Mr. DeMars coached for the Phillies from 1969 to 1981, playing an instrumental role in the careers of hitters like Mike Schmidt, Larry Bowa, and Garry Maddox. Pete Rose said he was the best hitting coach he ever had and brought DeMars with him to Cincinnati in 1985 when Rose was the team’s player-manager.

Mr. DeMars spent the majority of his 16-year playing career in the minor leagues and then managed in the minors before joining the Phillies’ staff.

“He was a good, old guy who was around and worked hard and was ready to go to the batting cage,” Schmidt said. “He taught more by feel, if you know what that means. If you can’t feel it, then you can’t correct it. He made you feel a certain sense of contact — how it feels when your shoulder stays in and you cover the ball and how it feels when your shoulder comes out and you roll over the ball or swing and miss or pull it foul. All of us on the team benefited from that.”

Mr. DeMars is the third Phillies alumnus to die this month. The team lost previously lost slugger Dick Allen and 1993 hitting coach Denis Menke. Mike Ryan, who joined DeMars on Dallas Green’s 1980 coaching staff, died earlier this year.

The team’s oldest living alumnus is now 95-year-old Bobby Shantz, who is a month younger than DeMars. Shantz, a left-handed pitcher from Pottstown, finished his 16-year career by pitching in 14 games with the 1964 Phillies.

Mr. DeMars played a pivotal role in one of the franchise’s most important games when he prepped Del Unser before Game 5 of the 1980 NL Championship Series against the Houston Astros. Unser, a 35-year-old bench player, asked Mr. Demars to throw him extra batting practice at the Astrodome in hopes of snapping a funk. That night, Unser stroked the game-tying hit in the ninth inning and scored the winning run in the 10th. The extra batting practice, he said, did the trick. The Phillies returned to the World Series for the first time in 30 years and Mr. DeMars helped them get there.

“Every time you hit it good, it excited him,” Unser said. “You knew when you did, and that was positive reinforcement, which is a good way to teach. He made you focus on something completely right in front of you instead of what the big picture was. You had to fix the little things first and get your stroke headed in the right direction and then you can cover the plate.”

Mr. DeMars was born in Brooklyn, N.Y., and signed with his hometown Dodgers when he was 17. He served in the Navy during World War II and was selected by the Philadelphia Athletics in the 1947 Rule 5 draft. Mr. DeMars played 18 games in 1948 as a rookie for the A’s. He lived in Clearwater, Fla. after his retirement.

“He frequently visited the Carpenter Complex in Clearwater, Fla., to continue his tutelage of young Phillies hitters,” the Phillies said in a statement. “Mr. DeMars’ passion for baseball — and, in particular, the art of hitting — was very evident to those who knew him. The Phillies organization sends its condolences to the entire DeMars family.”