AP -
The 34-year-old will cover for Shivnarine Chanderpaul during June and September, when the Guyanese left-hander is required for West Indies Test duty against New Zealand and Bangladesh.
North - who has represented rival county sides Lancashire, Glamorgan, Durham, Gloucestershire and Hampshire - had a short spell with Derbyshire in 2006, making 465 runs at an average of 93 during a brief but memorable three-match stint.
"To have a player of Marcus's experience and calibre joining us is massive for the squad," said Derbyshire's elite performance director Graeme Welch.
"I captained Marcus when he played for us in 2006 and the class he showed with his batting was unbelievable."
North finished the 2013-14 Sheffield Shield season as the leading run-scorer, making 888 runs at an average of 68 for Western Australia that led to him being named player of the year.
During his stand-out season, his brother tragically died in a car accident in Perth.
He announced in a press conference on Thursday that he had played his last game for Western Australia, although he plans to turn out for the Sydney Sixers in the Big Bash Twenty20 domestic competition.
Left-hander North played 21 Tests, two one-day internationals and one Twenty20 for Australia, scoring five Test centuries including 117 on his debut against South Africa in Johannesburg in February 2009.
