Odessa Simms, a 61-year-old mother of two and former teacher, was gunned down in a crowd of about 70 people near West 144th Street and Lenox Avenue about 11:44 p.m., according to NYPD officials and witnesses.
"When she fell, she asked for help. She got help when the paramedics got here," said Samuel Gelzer, who said he was with her at the time.
Simms, who lived about a block away on West 142nd Street, was pronounced dead at Harlem Hospital, police said.
There were no immediate arrests, police said Monday morning.
It wasn't immediately clear what sparked the shooting.
Witnesses said they saw a man with a gun chasing after another man south toward 143rd Street.
Mourners set up a memorial for Simms near the shooting scene, with a mass of candles on a park table under a sign reading, "Enough is enough" and "Stop the violence."
Friends remembered Simms as the mother to a son and daughter who frequently played dominos in the park.
"She was a great person. She was nice. She was friendly. She never bothered anybody. She'd help you. If you needed something, she'd give it to you," said Gelzer, who'd known Simms for 30 years.
Simms, a retired teacher, was known to be selfless and giving, friends said.
"She was a like a mom to me. She took care of me, bring me anything. She'd be there for me," said Wizard Chinnery, 49.
"She'd come out here and she'd feed the homeless," he added.
Simms' frequented a nearby senior center and food pantry, but always return to her games in the playground, friends said.
"And then she'd go to her pantry just to get food to give out to people. And then she'd come here to claim her table. She'd always have a table every day. This was her second home," said Tim Free, a super for a nearby building who also frequented the park.
“She was very [much] like an aunt, a sister a mother. She was a very beautiful person. She argued with nobody. She gave people money, and [to] the homeless that sleep out here,” Free added.
Those who knew Simms were heartbroken by her shocking death.
"All she'd do is play dominos. She didn't bother anybody," said Andre Cheatom, 59.
"I was very hurt. I ain't cried yet, but I gotta cry some later."