Foley, Munster's most-capped player and leading try scorer, formerly a technical advisor, will assume the role of assistant coach with additional responsibility for defence, while maintaining his function as head coach to the Munster British & Irish Cup side.
McCarthy, who featured in the Munster side that famously defeated Australia at Musgrave Park in 1992, and prior to this, a part-time scrum advisor, will now be full-time scrum coach.
He will work alongside forwards coach Laurie Fisher and Foley, and have additional responsibility for identifying and developing front row talent to feed into the Munster professional set-up.
Mick Galwey, captain of the Munster team that reached the 2000 Heineken Cup final, has been appointed as Munster squad advisor.
The Kerryman, who won the last of his 136 Munster senior caps in February 2003, was part of that Munster side, coached by the province's current CEO Garrett Fitzgerald, that beat the Wallabies in 1992.
Galwey was also had a management role with the Foley-coached Munster side that reached last season's British & Irish Cup final.
In addition, Munster have announced the appointment of Colm Coakley as squad physiotherapist.
Cork native Coakley will provide physiotherapy services, along with current physiotherapists Anthony Coole and Neil Tucker, to the Munster squad in Cork and Limerick.
A graduate of UL, and currently operating from a practice in Midleton, he spent the past season working with the Munster Academy and Munster British & Irish Cup squad.