Eighth-graders from all over the state spenttheir Saturday afternoon in a Brighton warehouse sorting bags of donated clothes, books, and toys — and many said there was no other way they would rather spend the day.

“I think this is the most fun I’ve had in a while,’’ said 13-year-old Naomi Mwangi of Brockton as she organized clothing in the Cradles to Crayons warehouse.

Project 351’s seventh Day of Service, held each year the weekend before Martin Luther King Jr. Day, began with an energetic ceremony at Faneuil Hall that morning. At least one student ambassador from almost every one of the state’s 351 cities and towns crowded into the hall beforegetting on buses to travel to volunteer sites.

The students were assigned to teams honoring “service heroes’’ ranging from Nelson Mandela and Susan B. Anthony to Yo Yo Ma and Muhammad Ali, as well as local figures such as former governor Deval Patrick, who helped found Project 351, chef Ming Tsai, and 8-year-old Martin Richard, a Boston Marathon bombing victim.

Richard’s sister Jane, now 10, lost a leg in the bombings. To the crowd at Faneuil Hall, accompanied by parents Bill and Denise, the young girl offered advice: “Don’t judge a book by its cover, and if you get to know someone and understand them, you’ll build bridges.’’

Michael Martinez, a 10th-grader at Weston High School who participated in Project 351 three years ago, returned this year as an alumnus for the second time. “Our generation is kind of looked down upon, and to have something like Project 351 — it really demonstrates that young people are stepping up,’’ he said.

“We want to be leaders and we want to help our community and have a positive impact on the people around us,’’ he said.

In addition to Cradles to Crayons, a nonprofit that provides supplies to children in need, this year’svolunteer sites included the Greater Boston Food Bank, the Pine Street Inn homeless shelter, the Clarence R. Edwards Middle School in Charlestown, and the Service Village hub at the Massachusetts State House serving the DCF Kids’ Fund, the Y2Y Harvard Square Homeless Shelter, and Hope and Comfort, a nonprofit focused on distributing hygiene products.

Though Project 351 has evolved into a yearlong program since its start in 2011, the Day of Service felt “in a really beautiful way, very familiar’’ because the process of empowering young people has been the same since the beginning, said Carolyn Casey, founder and executive director of Project 351.

“They come in quiet and nervous,’’ Casey said. “By the end of the day, you can see the confidence.’’

The Day of Service is affirmation for the young participants, she said. “They know that the things they do innately — to be kind, to be good, to be upstanding — that people like Governor [Charlie] Baker and others refer to that as ‘leadership,’ ’’ she said.

Baker took the stage at Faneuil Hall with his wife, Lauren Baker, where they spoke of their own service experiences in their youth — he as a Big Brother, she as a Brownie and Girl Scout — and encouraged the students to continue their service beyond just today.

“Model the behavior that you would like do see others model to you in response,’’ Baker said.

The governor then arrived at Cradles to Crayons and joined the organized chaos of children reaching into carts as big as they are, filled with clothes, toys, and books.

“I’m really happy because I just want to help these kids that don’t have all the things that we have — that we’re privileged to have,’’ said 13-year-old Daniel Swain of Westport, who organized clothes with Baker.

“It’s a good way to spend my Saturday afternoon compared to sitting on the couch,’’ Swain said.

“How do you not get involved with Project 351?’’ asked Dan Gilbert, principal of the Broad Meadows Middle School in Quincy and one of many adult chaperones for the Day of Service. “Sometimes we overlook the power of kids to affect change in a positive way.’’

“It inspires me because they don’t have any negativity yet,’’ said Julia Hutton, a health teacher at Luther Burbank Middle School who also served as a chaperone. “They’re not tainted. They believe in everything. They have hope in the future.’’

The children participating were indeed optimistic.

“When I first came here, it was like automatic family,’’ said Jayce Grant, a ninth-grader at Needham High School who participated in Project 351 in 2016 and was returning as an alumni. “You connect, and you shouldn’t be afraid to.’’

“Being part of something special makes you special,’’ Grant said.

Speaking to the students at the John F. Kennedy Presidential Library and Museum as the Day of Service came to a close, Bill Richard spoke of how his family stopped at a Boylston Street Starbucks the day his son Martin was killed in the Boston Marathon bombings.

“True to character, we got our order, and Martin asked his mom for the change,’’ said Richard. “God as my witness, he went outside and gave it to a man holding a sign and a cup.’’

Richard said his son told the man, “I don’t know about the food, but my mom gets coffee here all the time, so I’m guessing it’s pretty good.’’

Nicole Fleming can be reached at nicole.fleming@globe.com.