Ajit Singh was jailed for failing to take general fire precautions in his properties on nine streets in the town of Kettering in Northamptonshire.
One of the properties on Edinburgh Road caught fire on May 22 last year, killing Mateusz Wlodarczyk in the blaze.
Northampton Crown Court heard during sentencing this week that there was only one fire detector in the house and the battery was disconnected.
Safety failings were also discovered in Singh's eight other properties in Kettering.
Two other men, who acted as "property managers" for Singh, were sentenced for the same charge.
Martyn Emberson, chief fire officer of Northants Fire and Rescue Service, said: "This case clearly demonstrates how seriously fire safety breaches are viewed by the courts. I hope it sends a clear message out to landlords and managing agents across Northamptonshire.
