The centre-back announced his departure from Manchester City on Sunday after 11 years in England as he returns to the club he started his career with , signing a three-year contract to take over at the helm this summer.
Injury limited Kompany to 26 appearances in all competitions this season, but the 33-year-old captain played an important role as he scored the winning goal in his side's penultimate Premier League game against Leicester City, setting them up to beat Liverpool to the title on the final day.
Despite being kept out of Belgium's last two games in March, Kompany has remained a regular under Martinez when he has been fit and has 87 caps to his name.
And even though he is taking charge of first-team duties at Anderlecht, Martinez says he will continue to be a key figure for the Rode Duivels if he can maintain his level in the Belgian top-flight.
"We are all very pleased with Vincent's new position," Martinez told reporters. “He has always shown the qualities to take on this role and I have no doubt the next chapter will also be a success. As the Belgian football federation, we always support our players with a new challenge.
"Like any player of the Red Devils, his form will be decisive in whether or not he will be called up for the national team. After his impressive way of saying goodbye to Manchester City, we are already looking forward to our cooperation in the Euro 2020 qualifying matches in June.
"Moreover, the league will benefit from the arrival of such a Belgian football personality."
Kompany made over 100 appearances for Anderlecht's senior team after graduating from the club's youth academy.
He then went on to spend two years at Hamburg before arriving at City, where he went on to make 360 appearances.