Marriner will start work on Friday under manager Paul Sturrock.
Argyle chairman Sir Roy Gardner said: "Paul Mariner is not only an Argyle legend, but has established himself as a highly-respected and leading coach in American Major League Soccer and internationally, including in Japan.
"He will bring his own style and a wealth of experience to the club, supporting the development of the football side of the club with Paul Sturrock.
"This is an appointment which will cause a tingle to run down the spine of any Pilgrim.
"Paul Mariner represents a past, present and future that is the very essence of what Argyle should be about, a beloved ex-player who knows and understands the Greens and its fans, who has carved out a post-playing career as a respected coach and who now passionately wants to put something back into his former club."
Mariner scored 56 goals in 135 appearances for Plymouth before being signed by Ipswich manager Bobby Robson in 1976.
He went on to win 35 England caps, scoring 13 goals, and has spent the last seven years as coach under former Liverpool midfielder Steve Nicol at MLS side New England Revolution.
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