The final pick (No. 230) of the 2005 NHL Draft, Hornqvist has proven to be a valuable player.

Hornqvist was selected by the Nashville Predators to close out a draft that began with Sidney Crosby taken with the No. 1 pick. Through hard work and a tenacious attitude, Hornqvist stood alongside Crosby as part of the 2016 Stanley Cup champion Pittsburgh Penguins.

Hornqvist was playing in the third division in his native Sweden when he was drafted, but by the 2006-07 season he was named Swedish Elite League Rookie of the Year with Djurgardens after scoring 23 goals in 49 games. After another season in Sweden, Hornqvist made the move to the NHL and started the 2008-09 season with the Predators. He scored his first NHL goal Oct. 15, 2008, against the Dallas Stars, before being assigned to Milwaukee of the American Hockey League.

By his second season, Hornqvist showed a willingness to be a strong net-front presence, and he finished with 30 goals to become the fourth player in Predators history to score at least 30.

He scored 21 goals in 2010-11 and 27 goals in 2011-12, and helped the Predators advance to the Western Conference Second Round each season.

The Penguins acquired Hornqvist in a trade with the Predators on June 27, 2014 and he continued to produce. He got his first NHL hat trick against the Arizona Coyotes on Feb. 29, 2016 and had his first Stanley Cup Playoff hat trick in Game 1 of the Eastern Conference First Round against the New York Rangers on April 13, 2016. He had 13 points (nine goals, four assists) in 24 games in the 2016 playoffs, including two goals in the Stanley Cup Final against the San Jose Sharks.

In 2016-17, Hornqvist had 44 points (21 goals, 23 assists) in 70 games. He scored five goals in 19 playoff games, including the game-winner with 1:35 remaining in the third period against the Predators in Game 6 of the Stanley Cup Final when the Penguins won the Cup for the second consecutive season.

Hornqvist was traded to the Florida Panthers by the Penguins on Sept. 24, 2020 for defenseman Mike Matheson and forward Colton Sceviour. Over Hornqvist's six seasons with the Penguins, he had more than 100 hits five times and led all Penguins forwards in hits twice, including a team-best 227 in 2016-17.

Hornqvist announced his retirement July 5, 2023. His 264 goals were tied with Nicklas Lidstrom, Thomas Steen and Kent Nilsson for 10th most by a Sweden-born player.