He covertly made territorial lords from around the country friends of the Eastern Camp, and assisted Ieyasu's 4th son Tadayoshi MATSUDAIRA (Naomasa's son-in-law) well in the battle by spearheading the Eastern Camp along with Tadayoshi instead of Masanori FUKUSHIMA, who was originally supposed to lead (normally, Naoyoshi and Tadayoshi would have been punished for violation of a military order, however, Ieyasu accepted Naoyoshi's conduct and didn't punish them).
同時に全国の諸大名を東軍につける工作を行い、また合戦においても家康の四男・松平忠吉（直政の娘婿）をよく補佐して忠吉と共に当初、東軍の先鋒を任されていた福島正則を差し置いて先鋒を務めた（本来ならば、直政も忠吉も軍令違反で処罰の対象になるが、家康は直政の駆け抜けを認めたため、処罰を命じなかった）。