Nigel Montgomery Uno a.k.a. Numbuh 1 is the bald, British leader and head operative of Sector V and current Earth representative to the Galactic Kids Next Door. Described as a tactical genius by some and as a paranoid workaholic by others, Numbuh 1 takes his position and responsibilities as a KND operative too seriously.
Throughout the show, Numbuh 1 speaks with a noted English accent, because his parents come from England and he was born there, but moved to the United States when he was 3 years old. According to Numbuh 1, he and Numbuh 2 have been best friends since Kindergarten. Numbuh 1 had a relationship with Lizzie Devine, who he considered bossy, but deeply cared for until Operation: G.I.R.L.F.R.I.E.N.D. when they broke up.
Numbuh 1 usually wears a red turtle-neck sweater, grey shorts, white socks, and brown shoes, which acts as rocket shoes from him when he clicks his heels together. He is seldom seen without his sunglasses and most noticeably of all, he is bald.
It’s implied in Operation: F.O.U.N.T.A.I.N. that Numbuh 1's baldness was caused by the Delightful Children From Down The Lane and something to do with Numbuh 5 before she recruited him. While transforming back into a kid (he was turned into a baby), it is seen that Numbuh 1 had brown hair, but it immediately disappeared once in his normal form.
In Operation: D.A.D.D.Y., Numbuh 1 mentioned that he had really cool hair, but it will never grow back again.
In Operation: B.U.T.T., it was revealed that Numbuh 1 had a big butt, which is considered funny to the rest of his team and the Delightful Children.
umbuh 1 is described as the stern, "workaholic leader of Sector V," as he would rather go on missions than spend his day-off at the beach as seen in Operation: B.E.A.C.H. and Operation: B.U.T.T..
Numbuh 1 is one of the few operatives in the Kids Next Door that takes his missions seriously as seen in Operation: F.E.R.A.L. where he yelled at Numbuh 86 ("... risking my life, endangered my team and spent valuable KND resources, just to get a stupid key chain?!") when he was sent to Rainbow Monkey Island to retrieve a stone tablet with a secret code on it.
Alongside Numbuh 5, Numbuh 1 is considered the only one with common sense on his team. As the leader, he is quick to jump into action and he is quite resourceful, but tends to be paranoid to the point of stretching the truth and using his imagination when analyzing a potential adult threat.
In Operation: Z.E.R.O., it was stated many times by Numbuh 362 (who notes that he puts his team before himself) that Numbuh 1 is reckless, hot-tempered, stubborn, and acts alone. Nevertheless, he's caring and protective towards his friends, putting his full trust into them.
Numbuh 1 is also a huge believer, as he is one of the few KND operatives who believes in Numbuh 0, who turned out to be his own father.
Although Numbuh 1 is clever, he is also shown to also be rather naive in Operation: D.I.A.P.E.R., as he believes that babies were kidnapped and brought to the hospital to be aged into adults, and that babies come from "baby eggs.