The phrase "actively concerned with" is correct and usable in written English.
You can use it to describe someone who is engaged or involved in a particular issue or topic, indicating a proactive interest or involvement.
Example: "The organization is actively concerned with environmental sustainability and works on various initiatives to promote it."
Alternatives: "deeply engaged in" or "proactively involved in".
She was, however, actively concerned with ecclesiastical appointments.
Phillips is actively concerned with the betterment of the tuba, of those who play it and of American music.
Newman was actively concerned with some of the projects, including the Hole in the Wall Gang summer camps, devoted to underprivileged youngsters.
I believe that every American, from the president to the newest citizen, should be actively concerned with the care and recovery of our wounded warriors and their families.
This pact shall be open for accession to any member of the Arab League or any other State actively concerned with the security and peace in this region and which is fully recognized by both of the High Contracting Parties.
But with his conductor competitions and his generosity toward talented younger maestros - Klaus Tennstedt, for instance, now records regularly with the Philharmonic - he would seem to be actively concerned with ensuring the Philharmonic's future.
Even though he didn't do as well with either group during his successful 2002 re-election bid, Bush's reputation as a bridge-builder who actively concerned himself with lifting up minority communities -- boosted, in part, by his high-profile push for expanded educational opportunities -- remains a central tenet of his political identity.
For the first three weeks of shooting, Coppola was actively concerned about being replaced.
In 2003 the Fed was actively concerned about disinflation and the threat of deflation.
The idea at the heart of open-book management that employees should actively concern themselves with a company's business objectives has a short pedigree.
Mobilizing all the resources of Russia for the triumph of his cause, constantly keeping himself abreast of events, and actively concerning himself with all important undertakings, often at his personal risk, he could be seen sometimes in a sailor's jacket on a warship, sometimes in an officer's uniform on the battlefield, and sometimes in a labourer's apron and gloves with an axe in a shipyard.
