Financial terms were not disclosed, but the deal will run through the 2009-10 campaign. Jackman currently has four goals and two assists in 57 games this season, all career highs.
"Tim earned this extension by showing his willingness to do whatever is necessary to help the Islanders succeed," Islanders GM Garth Snow said in a release. "We know Tim is excited about being an Islander next season and we're just as excited to have him back."
The 6-4, 210-pound Jackman owns six goals and seven assists over 125 career games with the Islanders, Blue Jackets, Coyotes and Kings. He was selected by Columbus in the second round of the 2001 NHL Entry Draft.