Glaswegian Adams, 39, arrives at Home Park after being sacked by Ross County in August last year following a previously successful seven-year stint in Dingwall.
Adams’ 14-year playing career took in Motherwell, Ayr United, Aberdeen, Livingston and Ross County, before he graduated to the the Highlanders manager’s job in October 2007 and won the Scottish Second Division in his debut season.
He guided the Staggies into the top flight for their first time in their history in 2012 by winning the First Division title by 24 points ahead of second-placed Dundee, claiming the PFA Scotland Manager of the Year award in the process.
The following season, he earned a second successive manager of the year nomination after guiding County to fifth place, just one point away from European qualification.
Adams secured a seventh place for County in the 2013/14 season, but parted company last campaign in August after a poor start to the campaign.
He also steered the Staggies to their first ever Scottish Cup final appearance, in 2010, by beating top-flight sides Hibernian and Celtic en route to a Hampden defeat to Dundee United, as well as a Scottish Challenge Cup final victory the following season.
Adams succeeded John Sheridan at the Argyle helm after he left following the club’s League 2 play-off semi-final defeat by Wycombe.
A Plymouth statement said: “Everyone at Home Park, and the worldwide Green Army, wishes Derek continued success in his career as he becomes the 47th man – and 12th Scot – to have been entrusted with being in charge of Argyle since the Pilgrims entered the Southern League in 1903.”