Emanuel Gomes has carried out surprise street sweeps, rounding up hundreds of gang members, prostitutes, repeat criminal offenders, and drug dealers. At the same time, Gomes, 50, is adding 16 new patrol officers, while beefing up the number of officers assigned to Brockton’s public schools.

One pledge remains a top priority and is more of a personal mission: Gomes, a Portuguese immigrant, wants to break down racial and ethnic barriers and promote understanding in one of the most diverse communities in the Common­wealth.

“Brockton is a new version of Noah’s Ark,’’ said Gomes. “There are pretty much two of everything.”

Like the vessel that held a range of species in the biblical story, the city has become a landing place for scores of ethnic groups from all corners of the globe.

Gomes says he recognizes the pursuit of a better life because he’s been there himself. He also knows the challenge of starting over, personally and culturally. He was 8 when his family moved from ­Madeira, Portugal, speaking little English. His mother worked two jobs and took language classes at night. His father died three years after they arrived.

“There was no English as a ­second language program then,” he said, “so it was scary to be in a new world where you know no one.”

Still, Gomes rose through Brockton schools, earned an associate’s degree in criminal justice from Massasoit Community ­College in Brockton and a bachelor’s degree in criminal justice from Roger ­Williams University in Rhode Island, joined the Police Depart­ment, and now, 25 years later, is chief, an attainment he says he still finds unbelievable.

“Never in my wildest dreams would I have imagined sitting here,” he said in an interview.

He said he has translated that cultural understanding into action for others, ensuring that his 191-member department has Spanish, Portuguese, Cape Verdean, and Haitian-speaking officers, covering the city’s principal immigrant languages. He also taps into a multicultural mutual aid agreement with other departments, he said, to find officers who can speak Laotian, for example, or some other language, as needed, he said.

Brockton’s Police Department employs 34 women and 157 men, of which 142 are white, 26 are black, 22 are Hispanic, and one is Native American. According to 2011 statistics from the US Census Bureau, 42.9 percent of the city’s 94,316 residents are non-Hispanic white, 31.2 percent are black, 2.3 percent are Asian, and 10 percent are Hispanic, with the remainder comprising other groups.

As part of the department’s outreach, Gomes said, officers work with a city code enforcement team and help immigrants establishing businesses to understand the city’s rules and regulations.

“You might come from a country where you can just open up a body shop on the side of the road,’’ he said of the cooperative effort. “Code enforcement isn’t meant to just levy fines, but to get compliance.”

Gomes has also brought neighborhood crime watches and foot patrols to the downtown area, the Montello neighborhood in the north, and the Campello neighborhood in the south, which includes a number of ethnic businesses.

A regular police presence eases fears, as do the sweeps, he said, for native and immigrant communities alike.

The law enforcement presence includes Officer Chris Perez, who has patrolled the Campello area for about six months and has oversight of James Edgar Park, a leafy square bordered by Brook, ­Dover, South Fuller, and Winthrop streets, near the childhood home of legendary champion boxer Rocky Marciano.  

The park had become a gang hangout for drug deals in recent years, but now families are not afraid to go there because of the ­police presence, city officials said.

Perez said he is studying Cape Verdean Creole to help open doors and provide tactical and logistical help in investigations. “My last name is a misnomer,’’ he said. “I don’t speak a word of Spanish. I’m ­actually Italian. But the last thing anyone thinks is this white guy with the Spanish last name speaks Cape Verdean.”

It’s also about respecting your constituents, he said. “If I go into someone’s home and can speak a few words, they see I’m making an effort. The first thing I learned was thank you.”