Keyser died at Washington County Hospital, where she was taken after an accident on Alternate U.S. 40 at Toms Road that was reported at 8:38 p.m., police said.
"Jessie was a very positive influence," said Dan Daughtridge, who was Keyser's junior varsity soccer coach. "She always had a kind word for other players."
Police said Keller was northbound in a 2000 Mercury Mystique when she failed to negotiate a curve. The car went onto the east shoulder of the road and hit a snow bank, police said.
Keller tried to steer back onto the road, but the wheels were turned to the left when they grabbed dry pavement, sending the car into the southbound lane, police said. The car collided with a 1998 Buick LS driven by Gary Cornell, 41, of Mercersburg, Pa., police said.
Cornell and Michele Cornell, 40, had minor injuries, as did a 13-year-old girl and 17-year-old boy in the back seat, whom police did not identify. Police said all of the people in the Buick were wearing seat belts.
Keller was not wearing a seat belt, police said.
She was on the homecoming court last fall at James Buchanan, and she had been on the school's tennis team for four years, according to her father, Anthony Keller.
"She excelled at that quite well," he said. He described his daughter as "a hard-charger. She never gave up on anything."
Anthony Keller said his daughter was active in 4-H as a child and "held numerous awards in most everything she did." She was active in the United Methodist Church of St. Thomas, he said.
She worked as a hostess at Flannery's Tavern on the Square in Mercersburg, and she had been a cook at CR Buck's restaurant near Chambersburg, he said.
"She was very dedicated, very honest, very upstanding ... and very independent," he said. She had no firm plans for post-secondary education, but she was interested in radiology, he said.
"If you were down, she'd try to get you up. That's who Alisha was" friend Julie St. Clair said. "She was always there to support you."
Anthony Keller said his daughter is survived by her mother, Annette, and a brother, 13-year-old Austin.
Keyser was a member of the Smithsburg High School girls soccer team that won a state championship in the fall.
"She was a very competitive individual," according to her coach, Bill Fowkes.
Keyser transferred to Smithsburg High School from Boonsboro High School at the beginning of this school year, Fowkes said, but she recently had gone back to Boonsboro.
Kyle Lingg coached Keyser when she was a sophomore at Boonsboro.
"She went out of her way to be respectful and kind to teammates, opponents and coaches, both on and off the soccer field," he said.
Her happiness and positive attitude were contagious, Lingg said.
"I understand she was a really good student," Fowkes said. "My heart goes out to her family."
A viewing for Keller will be Wednesday from 2 to 9 p.m. at the United Methodist Church of St. Thomas, with the family receiving friends from 6 to 9 p.m. The funeral is scheduled for 11 a.m. Thursday at the church.
Arrangements for Keyser were not available Monday night.