“She’s more than just a cyclist and an advocate,” Rose Frank, 36, who became friends with Gag in seventh grade, said. “Those were parts of her identity, but she’s such an amazing person in so many other ways, and we want to celebrate all of those ways.”

Gag, who grew up in Roslindale just minutes from the park, was a joyful and energetic child, said Mark Smith, 66, a neighbor who spoke at the event.

“She was the sweetest little girl with a big wide smile,” Smith said. “Whenever you were in her presence, you felt somehow special.”

Smith said Gag’s passion for giving back to her community likely came from her parents, Steve Gag and Laura Gang, longtime Roslindale residents who contributed greatly to developing the neighborhood. Steve Gag helped bring a farmers market to Adams Park, while Laura Gang was involved in the public library.

Gag’s loved ones said she grew up to become a generous person who cared deeply about her family and friends.

“Louisa showed up for people,” Molly Goodkind, 36, a childhood friend of Gag’s said during Sunday’s event. “We’ll never understand how she had time to be everyone’s go-to person.”

Gag, she said, would eagerly volunteer to cat-sit, even though she didn’t like cats. Another friend said she kept a spreadsheet of the birthdays of all the babies she knew.

“She was the person outside of my biological family who, if I needed something, she would be there in an instant,” Goodkind, who has known Gag since they were 2-years-old, said.

Gag’s friends said she was curious and remained open-minded, even though she held firm beliefs.

“Who do you know that was a vegetarian except for when it inconvenienced others? And of course, except for hot dogs, because according to Louisa, you can’t not have a hot dog at a barbecue,” Gag’s friend Danielle Shaked said, drawing laughs from the crowd, including Laura Gang, who dabbed at her eyes with a crumpled tissue.

Gag also found time for many hobbies, and was always trying new ones, her friends said. Beyond loving outdoor activities such as biking and hiking, she was passionate about sustainability and shopped secondhand or sewed her own clothes. She dabbled in photography, painting, and cooking.

Urban planning was one of Gag’s enduring passions, Goodkind said.

“In college, she created her own major,” she said. “I don’t remember exactly what she called it, but it was something like city and people.”

Gag attended college at the University of Rochester and later earned a master’s degree in urban and environmental planning and policy from Tufts University, according to her LinkedIn.

Before joining the city in 2022, Gag worked for LivableStreets Alliance, a Boston-based nonprofit that advocates for increased safety, equity, and affordability. She also interned for Mayor Michelle Wu when Wu was a city councilor.

Wu attended Sunday’s event, but did not speak. Like many other attendees, she held a yellow sunflower, one of Gag’s favorites, as she tearfully listened to the tributes.

While Gag didn’t like being the center of attention, her friends said she would have been grateful for Sunday’s event.

“She would be completely honored to know that she has impacted so many people,” Frank said, her gaze drifting over the people gathered in the park.

Under a small tent nearby, attendees crowded around a folding table, filling out remembrance cards. Dozens of bikes leaned against the park’s fences while more lay scattered in the grass.

Allyson Chiu can be reached at allyson.chiu@globe.com. Follow her on X @_allysonchiu.