Ricardo Arroyo won a decisive victory on Tuesday in the contest to replace Councillor Tim McCarthy in District 5, which includes sections of Mattapan, Hyde Park, and Roslindale, defeating first-time candidate Maria Esdale Farrell by about 700 votes, according to his campaign.

The 32-year-old Arroyo will be the first person of color to hold the seat.

In a Roslindale restaurant packed with supporters and family members, the new councillor celebrated the win and sounded a note of unity.

“This is an interesting day for me because I know that there’s a conversation that often happens when we break another barrier,” he said. “And that conversation often starts with the New Boston and old Boston. I’ve never agreed with that kind of framing and I’ll tell you why— because there are people in this room who are part of the old Boston— people in this room— who’ve worked every day of their lives so that a Latino kid from Hyde Park can stand on this stage as your next city councilor.”

Arroyo’s win is historic in another way: In joining the council, he follows in the footsteps of both his father, Suffolk County Register of Probate Felix D. Arroyo, who was a councilor earlier in his career, and his brother, Felix G. Arroyo, who was an at-large councillor before running for mayor of Boston in 2013.

Ricardo Arroyo, born and raised in Hyde Park, worked as a public defender until launching his run for office last year.

He told the Reporter: “It’s one of those situations where we learned a long time ago that if you want to make history, if you want to be the first at anything, you have to make coalitions. We did that really early. We reached out to every neighborhood, we never counted anybody out. We had multi-language literature. We knocked in every neighborhood. … There’s not a house in the district that wasn’t on our map.”

Arroyo said that when he knew he was the winner on Tuesday night, he thought about all the people who had paved the way for the breakthrough.

“We are now in a position where the Boston City Council… is a majority people of color body. It’s a majority women body. The issues that our communities have for so long not seen addressed— things like the disparity in contracts that the city gives out; the numbers of black unemployment; the health disparities in Mattapan; things that for so long have felt unseen— now have a moment to be seen.”

In District 4, Andrea Campbell cruised to a landslide victory over a challenger, Jeff Durham. Official results have not yet been posted, but campaign sources said Campbell was winning about 80 percent of the vote in the district with most precincts reported. Frank Baker was returned to office in District 3 after running unopposed.

See DotNews.com for updates on the election results.