A live video feed on the Internet joined people on the two continents during Sunday's event.
"I'm happy because I'm here!" said Patricia, a student at the Baker Elementary School in Brockton, as she watched other youngsters wearing Santa hats dance on a nearby stage.
Upwards of 2,000 people turned out in Brockton for the annual Santa Hat Challenge, said event organizer John Merian, who did not have an official count Sunday night.
Until Sunday, Brockton held the record for most people wearing a Santa hat in one location - the city set it last year when 1,792 gathered on Main Street near the site of the former Edgar's Department Store.
While Sunday's turnout in Brockton had about 400 fewer people participating than last year, thousands of added Santa hats worn simultaneously in Mullingar, a town northwest of Dublin in Ireland, helped set a new world record, Merian said.
"We blew that (record) out by doing it simultaneously in two separate spots at the same time," Merian said.
Brockton mother Heather Derosa said she came to be counted in the challenge again this year with her two children, Zachary, 5, and Ryan, 6 months.
"My son (Zachary) loves it. I want to try to break them into doing this every year," said Derosa, 30, as she cradled her infant son, Ryan, wearing a black winter jacket and a red Santa hat, in her arms.
Nearby, a large TV screen displayed a live video feed from Mullingar, Ireland. As children and parents danced and waved in Brockton, a large crowd of people did the same in downtown Mullingar.
The crowd became especially excited when Irish music piped in from overseas, stirring the Brockton crowd to begin dancing. DJ Joe Lupica led the crowd in singing "I'm Shipping Up To Boston" by Dropkick Murphys.
Mayor Linda Balzotti called the event - with a "sea of red Santa hats" - one that Brockton can boast about.
"It really shows the Brockton pride. It makes you really proud," Balzotti said after addressing the crowd.
Meanwhile, Mullingar, the Irish town, turned the Santa hat record attempt into a day-long celebration that also included attempts to set world records for the largest greeting card and Christmas tree cutting, as part of a festival that included live music.
Shortly after the joint event, Merian said he spoke with Marty Mulligan, an organizer in Ireland.
Mulligan told him thousands of people participated in Mullingar, despite heavy rain there, Merian said.
"He told me they were so incredibly happy when they saw us on the (television) screen," Merian said. "He said,