The former Hearts striker is expected to arrive at Tynecastle this week to take up his position, although Gary Locke will remain on the coaching staff.
The 37-year-old comes to the Edinburgh club with some experience under his belt, having worked as assistant at Lokomotiv Moscow last season, alongside Jose Couceiro – who was himself a candidate for the Hearts manager’s job at one point.
The appointment will come as a surprise to many, although Jankauskas is already well known to both McGlynn and Vladimir Romanov and the Hearts owner in particular may view him as an ally in the dressing-room.
The powerful hitman also played for FBK Kaunas before moving to Tynecastle on loan in 2005 and spent two seasons at Tynecastle.
During that time he helped the club win the Scottish Cup, and qualify for the Champions League by finishing second in the SPL and was at the club when McGlynn took charge of the side on an interim basis earlier the 2006 campaign. Prior to his move to Hearts, Jankauskas played for Porto under Jose Mourinho and made history by becoming the first Lithuanian to win the UEFA Champions League back in 2004.