Prior to joining the NHL, Ekblad played major junior ice hockey for the Barrie Colts of the OHL.

He was granted exceptional player status unanimously by Hockey Canada, which allowed him to play in major junior level a year early.

In 2010–11, Ekblad competed for the Sun County Panthers minor midget AAA team in Belle River, Ontario.

[10] After making the Panthers' opening night roster out of training camp for the 2014–15 season, Ekblad made his NHL debut on October 9, against the Tampa Bay Lightning.

[13][14] On January 23, 2015, Ekblad was named as an injury replacement for Colorado Avalanche defenceman Erik Johnson at the 2015 NHL All-Star Game.

[17] Ekblad also set a new franchise record for rookie defencemen in goals, assists, and points, surpassing Ed Jovanovski.

[18][19] On April 23, Ekblad was named one of three finalists for the Calder Memorial Trophy – awarded annually to the NHL's rookie of the year – along with Mark Stone of the Ottawa Senators and Johnny Gaudreau of the Calgary Flames.

[21] During the following season, Ekblad missed four games in January 2016 to recover from a concussion he had endured from a hit delivered by Matt Hendricks of the Edmonton Oilers.

[28] He underwent surgery to repair a left leg fracture the following day and was ruled out for 12 weeks, effectively ending his season.

[29] On March 18, 2022, Ekblad recorded three assists in a 5–3 loss against the Vegas Golden Knights, giving him 291 career points, the most by a defenceman in Panthers franchise history, surpassing Róbert Švehla.

[34] Ekblad played for Canada senior team at the 2015 World Championship, where they won the gold medal for the first time since 2007 with a perfect 10–0 record.