Educator and activist Geoffrey Canada exhorted UMass Boston’s Class of 2018 on Friday to leave the world a better place.

“The best of America is yet to come,’’ Canada, longtime president of the Harlem Children’s Zone, told the 2,733 graduates at the school’s 50th graduation at TD Garden.

In his graduation speech, Canada’s powerful voice boomed over the arena as he urged graduates to remember the important strides made for this country by heroes like Rosa Parks and Susan B. Anthony.

He also encouraged them to remember the sacrifices made by figures like Dr. Martin Luther King, John F. Kennedy, and Robert Kennedy, who “lost it all for the ideals that this country stood for.’’

Canada is known for his work as the longtime president of the Harlem Children’s Zone, a cradle-to-college approach aimed at breaking the cycle of poverty. The organization has become a global model for improving education in low-income neighborhoods.

Canada is also a well-known advocate for the reform of America’s public schools and has been the subject of several documentaries and television interviews.

He said that because he had assumed a lower leadership profile in 2014 at the Children’s Zone, his time as a mover and shaker is running out.

“Someone else will have to pick up the mantle,’’ he told the graduates and their families in attendance. “I need you to promise me.’’

Interim Chancellor Barry Mills, who is stepping down in June, honored student veterans and those who are the first in their family to receive a degree.

The graduation capped a tumultuous academic year for the college, beset by painful budget cuts and protests from students, faculty, and staff over the acquisition of Mount Ida College in Newton by UMass Amherst. Many on the Dorchester campus say the deal signaled misplaced priorities by the state’s university system.

In addition, three finalists for chancellor of UMass Boston withdrew this week after some faculty publicly called the candidates ­underqualified.

Despite the recent turmoil, smiles and cheers dominated the morning Friday as graduates radiated hope for the future.

“It was a long four years, especially with three majors,’’ said ­Lucas Henrique, 22, of Somerville, whose academic robe was decorated with colorful tassels and gold medallions for each of his majors, honors, and student groups.

He recalled “a lot of late nights of school eating noodles and doing homework and pulling my hair out,’’ he said, but his strongest feelings were of “relief, a lot of hope, and a lot of pride in UMass Boston.’’

Taisha Tyler, 31, of Dorchester, who earned a degree in human services, said she felt “happy that I’ve finished what I’ve started.’’

Tyler and her 5-year-old daughter decorated her mortar board together, emblazoned with the phrase “Brains and Beauty’’ across a picture of a woman of color sitting on top of the world, wearing a crown. Tyler said the decorations represent her “journey being a mom, being a single woman, being an African-American woman, and just trying to, you know, get ahead in life.’’

Honorary degrees were awarded to Canada and former US representative Barney Frank. The JFK Award for Academic Excellence was awarded to undergraduate student speaker Christian Walkes.

“We made it,’’ Walkes said after being presented the award in the shape of a bust of President Kennedy.

In his speech, Walkes celebrated the diversity of this year’s class, highlighting “the first-generation grad, the undocumented grad, the gender nonconforming grad,’’ and expressing his hope for everyone in the audience “to feel affirmed in the castle of your skin and tied to the fight for your liberation.’’

Margeaux Sippell can be reached at margeaux.sippell@globe.com. Follow her on Twitter @MargeauxSippell.