Ja'Mari Alexander Jones, 19, was arrested last week and charged with the Christmas Eve shooting after several days on the run from police. He is being held in King County Jail without bail.
Court documents say that Jones fired at least five shots inside the bar, killing 30-year-old Deshawn Millikin, of Seattle. Two other people were wounded in the shooting.
Investigators said Millikin and Jones got into a physical fight just after 1 a.m. inside the bar. Security camera video shows Jones shooting at Millikin and then running from the scene, according to court documents.
More than 600 people were at the bar when the shooting occurred, including several Seahawks players who were celebrating after the team's victory over the San Francisco 49ers.
Coach Pete Carroll said the players were in a separate area of the bar and were not involved in the shooting.
Jones was one of three teens convicted in the 2008 beating death of a Seattle street musician known as Tuba Man, 53-year-old Ed McMichael.
Jones was sentenced to less than a year in juvenile detention on a first-degree manslaughter charge in that case.
The latest charges against Jones include a firearm sentencing enhancement and carry a sentence range of 20 to 28 years in prison if he is convicted as charged.
Scott O'Toole, senior deputy prosecutor with King County, said it is possible that more charges could be filed later against Jones, which could potentially lengthen the sentence in the event of a guilty verdict.
"There's potentially two more victims (who were wounded by gunfire)," he said.
O'Toole also said he understood this is a very emotional case.
"Deshawn Millikin was a guy who was living his life appropriately and right, and he's very close to his sisters, and very close to his mother, and to have that happen ... is devastating to the family," he said. "They want his memory, as he was, to be known to the public and try to recover from this tragedy."