First-half goals from Andy Carroll and Wayne Routledge gave Newcastle, relegated from the top flight last season, the win which secured the crown with two games left to cap a dominant season which has seen them lose four times and accrue 98 points.
The victory also consigned Plymouth to relegation and a place in League One next season.
"I think we got to a stage where we couldn't shout from the rooftops but we were comfortable that we were going to go up," said the Magpies' manager Chris Hughton.
"We got to that stage and probably for a little while it's been about winning the title and I couldn't be any prouder of this group of players.
"They have gone from day one and we have probably had one blip during the season, they came back from that strongly and went on a very good run.
"We have been the team to beat all season. We have a magnificent support that have made every stadium that we have gone to a big occasion, including tonight."
2,431 Newcastle fans made the trip to celebrate securing the title.
