The deal is for six years, $48.5 million, sources told ESPN senior NFL analyst Chris Mortensen, with more than $29 million in guaranteed money. The maximum worth of the contract is $58 million, sources said.
Okung, the No. 6 overall pick in the NFL draft, joined his teammates about 15 minutes into the afternoon practice and was working at left tackle with the second unit. The thousand or so fans in attendance didn't even notice the 6-foot-5, 310-pound prize slip onto the field late.
"It feels great. This is the best job in the world," said the 22-year-old Okung, who missed the first six days of Seattle's training camp.
Seattle selected Okung to replace retired All-Pro left tackle Walter Jones. Yet the rookie says he's not thinking about being the next Jones, only that "I'm going to be the best Russell Okung I can be."
Asked what took so long, Okung said, "It's just the business side of it. I'm not here to talk about that."
New coach Pete Carroll said Okung, whom the Seahawks named as their starter at the most important position on the line the day they drafted him, will likely remain a backup for a week or 10 days because he is so far behind.
Carroll praised Seahawks first-time general manager John Schneider and team money man executive John Idzik for "standing strong" and not increasing Seattle's offer.
Okung signed for a guarantee that is almost exactly the midpoint between the guaranteed $34 million No. 5 overall pick Eric Berry got from Kansas City and the $26 million in guarantees seventh pick Joe Haden received from Cleveland.
First-Round Pick Signings
A breakdown of signed and unsigned first-round NFL draft picks. Blog
That's why Carroll was asking, what took so long?
"This could have happened sooner, unfortunately," Carroll said. "It was killing him to not be here. ... It puts Russell behind. It's unfortunate for the kid."
Okung and C.J. Spiller, the Buffalo Bills' top pick, were the last two first-rounders to agree to terms.
Spiller agreed to a five-year deal Friday worth a maximum $37.5 million, with $20.8 million guaranteed, a source told ESPN.com senior NFL writer John Clayton.
Information from The Associated Press was used in this report.