Nearly 1,000 undergraduates received diplomas from Emerson College Sunday at Agganis Arena along with messages urging them to embrace the present moment and look to themselves as forces of positive change.

The new graduates, dressed in black gowns and caps, heard from a slate of speakers in the morning, including former United States Poet Laureate Billy Collins.

Collins mused on the topic of happiness in his commencement address, telling listeners that it is not something found in materials or awards.

“Take your eyes off the prize, keep your head down, and focus on your work. ... Your work is the prize’’ Collins said.

“Seize the day, because eventually, one day will come along and seize you,’’ the poet added.

Collins, who eluded politics for most of his speech, reminded the audience that exercising First Amendment rights is vital to protecting fairness and democracy, especially in the current political climate.

“Vote, vote, vote,’’ he said. “Seriously, vote often.’’

Deeyah Khan, a documentary filmmaker and honorary doctorate recipient, told graduates that regardless of how “dark’’ things may feel in America, they have support around the world.

Khan, who grew up in Norway and is of Punjabi and ­Pashtun descent, received rousing applause when she told the crowd that the country is great as it is.

“It is my humble opinion that America does not need to be made great again, because America already is great,’’ Khan said, “And it is great because of young people like you.’’

The graduate students’ commencement was held at 3 p.m. at Agganis Arena, with 270 students receiving degrees, according to an Emerson spokeswoman.

Alana Levene can be reached at alana.levene@globe.com. Follow her on Twitter @alanalevene.