Prior to becoming a member of Sector V, and prior to becoming Numbuh 4, Numbuh 57's personality differed back at the time of the Kid War, prior to the KND Adult Cold War, where it was actually stated by Numbuh 1 in the last days of the war, that Numbuh 57 was actually quite a brilliant strategist, and was even able to overcome kids that were older then he was, despite his age.

Just like in modern days he was considered the Central Park Sector's muscle, and the bravest, toughest, strongest, fiercest, wildest, most adventurous, dangerous, courageous, of the group, in fact it was stated by Numbuh 111, that he laughed at people who was able to challenge him, and was even able to sense when they were in fear, he was also known when he was a KTD to torment and sometimes toy with opponents during the course of the war, as he preferred to fight hand and hand prior to switching to weapons under the orders of Numbuh 111 in 2001, after Central Park Sector swapped sides and joined the KND.

It was also stated that Numbuh 57 was actually very smart prior to the events of KND Adult Cold War, and was said to have been an expert at certian plans at the time of war when Numbuh 111 was not around.

However, Numbuh 57's personality became that of stupidity, when he was memory wiped by the KTD as a form of punishment for deserting and joining the KND, but the process was interrupted when Central Park Sector was able to save him.

However, despite saving him, the damage was done, and Numbuh 57, soon became more stupid, hot tempered and dumb, but still held respect and kindness toward his teammates and even to the Kids Next Door, to the point that by the time the War ended after Operation END WAR, Numbuh 57 along with the rest of Central Park Sector voluntarily surrendered to Sector G on December 6th, 2002, where after VT Day they were brought to Moonbase 2, where Numbuh 57 was granted membership into the Kids Next Door, and he got his new nick name Numbuh 4.