Systems and methods for making a paperboard container include a sidewall blank heater assembly having upper and lower sidewall blank heaters for simultaneously heating upper and lower edge strips of the sidewall blank adjacent lateral edges thereof, and a bottom sidewall seam heater for heating a generally curved strip adjacent an arcuate bottom edge of the sidewall blank simultaneously with the upper and lower edge strips. The sidewall blank is thereafter curved about a forming mandrel at a container-forming station so as to overlap the heated upper and lower edge strips of the sidewall blank to form a longitudinal container side seam, while the bottom edge of the sidewall blank is brought into contact with a paperboard bottom wall blank to form an annular container bottom seam. A bottom seam heater assembly is most preferably provided for circumferentially heating the container bottom seam simultaneously while the sidewall blank is curved about the forming mandrel at the container-forming station. In such a manner, high quality, leak proof seams of the paperboard container ensue.