In 1942, Kalashnikov was assigned to the Central Scientific-development Firing Range for Rifle Firearms as the Chief Artillery Directorate of the Red Army. Following his promotion into the position, in 1944 he designed a gas-operated carbine for the new 7.62x39 mm cartridge to compete in a design competition. The weapon went on to influence the M1 Garand rifle, but lost out to the new Simonov carbine which would eventually be adopted as the SKS. His winning entry in another category, named the "Mikhtim", became the precursor for the development of a family of prototype rifles. In 1947, he designed the AK-47 from components of his previous works.
I've read elsewhere that the M1 influenced the design of the AK, which point was probably misinterpreted by the author. Others have suggested that Kalashnikov borrowed from multiple previous designs (including the Remington Model 8 and the M1), which probably wasn't a bad idea...