Travis Hamonic was born on August 16, 1990 in St. Malo, Manitoba. A standout defender for the Moose Jaw Warriors of the Western Hockey League, he was selected in the second round of the 2008 NHL Entry Draft by the New York Islanders.
Hamonic made his professional debut in 2010 in the American Hockey League with the Bridgeport Sound Tigers, but would make the jump to the NHL after just 19 games. He would appear in the remaining 62 games for the Islanders, scoring five goals to go along with 21 assists and 103 penalty minutes.
During the 2011-12 season, Hamonic would appear in 73 games for the Islanders and continued to provide a stabilizing presence on the club's blueline. His plus 6 rating was best on an Islanders team that struggled at times to keep the puck out of the net.
During the 2014-15 season, Hamonic tied his career-high with five goals. He also established new personal bests with 28 assists and 33 points and his +15 rating was tied for top spot among Islanders defencemen.
On June 24, 2017, Hamonic's time in the Islanders organization would come to an end. He was traded to the Calgary Flames in exchange for a package of draft picks.