Short answers, pulled from the story.
The Leningrad Front emerged on the 27th of August 1941 from the division of the Northern Front. This new army group faced an immediate task to contain the German Army Group North.
Ivan Fedyuninski commanded briefly in October 1941 before Mikhail Khozin took over that month. Mikhail Khozin remained in charge until June 1942 when Leonid Govorov assumed leadership.
A blockade began on the 8th of September 1941 and cut off most supplies to the city. Soldiers of the front operated under these harsh conditions with very little food or ammunition reaching them.
Forces of the Leningrad Front made their first advances in years by taking Shlisselburg in January 1943. This operation restored communications between Leningrad and the rest of the country after months of isolation.
On the 24th of June 1945 the Leningrad Front was reorganized into the Leningrad Military District. This transition marked the end of its operational history as an army group.