Born in Kuopio, Finland, Jokinen was dynamic scorer on the Finnish teams KalPa and HFK Helsinki. He also represented Finland at both the 1997 World Junior and World Championships. Jokinen was named the Finnish Rookie-of-the-Year in 1997 then was chosen third overall by the Los Angeles Kings at the NHL Entry Draft.
In 1997-98, he scored 39 points in 30 games for HIFK Helsinki. Jokinen also scored 10 points in seven games when he helped Finland win gold at the 1998 World Junior Championships and was named the best forward at the tournament. He also earned a place on the tourney's All-Star Team. The talented youngster played eight games with the Kings then joined Finland at the World Championships where he won a silver medal.
During his first full NHL season in 1998-99, Jokinen was very impressive at times for the Kings. After starting the season with the Kings AHL affiliate in Springfield, Jokinen was called up early in the season. His impact was immediate and he was named NHL Rookie-of-the month for November after scoring eight points in 11 games. Jokinen was often teamed with experienced snipers Luc Robitaille and Glen Murray to help settle him down. He finished with 21 points in 66 games but was then included in the off-season package sent to the New York Islanders to acquire Zigmund Palffy and Brian Smolinski.
Jokinen responded with eleven goals and 21 points in 1999-00. One of the highlights of his season came on March 4, 2000 when he beat Dominik Hasek on his first career penalty shot to ignite a 4-2 Islanders' win. Following the season Jokinen was involved when the Islanders and Florida Panthers swapped four of their most promising youngsters. Jokinen and goaltending phenom Roberto Luongo were sent to Miami in return for Oleg Kvasha and Mark Parrish. Jokinen scored 16 points in 78 games and began to refine the defensive side of his game on the rebuilding Panthers.
Following a career high 29 points in 2001-02, and between representing his native Finland at 2002 Winter Olympics in Salt Lake City and the 2002 World Championships, Jokinen broke out offensively in 2002-03 establishing career highs in goals (36), assists (29) and points (65) while making his All-Star debut in front of his home fans. Coming off a breakthrough year in 2002-03, Jokinen responded with a 58 point season in 2003-04, yet the Panthers failed to qualify for the post season. Upon the conclusion of the Panthers regular season the talented Finn suited for his homeland at the 2004 World Championships in Prague, Czech Republic.
After being named captain in 2003-04, Jokinen became the team's leader and top point producer over the next three seasons with the Panthers. Over those three years, Jokinen tallied 233 points and appeared in every game with the struggling Florida Panthers. His six-year stint in Florida came to an end after the 2007-08 season however, Jokinen was dealt from the Panthers to the Phoenix Coyotes for Keith Ballard, Nick Boynton and a 2nd round choice in the 2008 Entry Draft. Jokinen left the Panthers as the club's all-time leading scorer in history.
Jokinen's stint in the desert would be short lived however, he would appear in only 57 games for the Coyotes, scoring 21 goals and adding 21 assists before being traded to the Calgary Flames at the NHL trade deadline.
On February 1, 2010, Jokinen found himself on the move again. This time Jokinen and Brandon Prust were shipped to the New York Rangers in exchange for Christopher Higgins and Ales Kotalík.
On July 1, 2010, Jokinen surprised the hockey world when as an unrestricted free agent he signed a 2-year contract with the Calgary Flames, the club that had traded him less than a year prior.
On July 1, 2012, Jokinen would sign a two year contract with the Winnipeg Jets. After his playing time was being reduced in Winnipeg, he would sign a one year contract on July 20, 2014
With the Predators in the mix for the playoffs, they would trade Jokinen, along with Brendan Leipsic, and a first round pick to the Toronto Maple Leafs for Cody Franson and Mike Santorelli on February 15, 2015.
Jokinen would not last long with the Maple Leafs as he would be traded on March 3, 2015 to the St. Louis Blues for Joakim Lindstrom and a sixth round draft pick.