Unlike the Nazi Low Riders, Public Enemy Number 1 (PENI)  has strong leadership but it is loosely structured.  And in contrast to the Aryan Brotherhood and many other prison-based gangs, the group does not appear to have a written constitution, defined code of behavior, or clearinghouse for approved actions.

PENI's structure is largely based on personalities.  Senior PENI members who are highly respected carry weight ("juice") within the organization and can decide on a course of action or who can join the organization.  According to law enforcement, one ex-member cynically noted that the rules can change day to day depending on Donald Mazza's whims and self-serving interests.

PENI claims to adhere strictly to a racist skinhead philosophy and ideology; however, in practice, the group's mercenary interests allow PENI members to associate at times with Asians and Hispanics while maintaining a strict "whites only" policy when it comes to membership.  There are members with Hispanic-sounding surnames; however, they identify themselves as Caucasian.  In addition, some members have non-white girlfriends, but the group generally frowns on such relationships.

PENI members routinely associate or spend time with other white racist gangs. Bars, biker clubs and white power concerts that attract a variety of other white power gangs will often also attract PENI members.  Other racist skinhead groups such as the Orange County Skins and Insane White Boys can often be seen together with PENI at both informal and planned activities.  Some years ago, PENI was a driving force in an unsuccessful attempt to unite with those gangs and others (including La Mirada Punks, Norwalk Skins, and Southern California Skinheads) into a unified group called the Southern California Skinhead Alliance.   However, some other white gangs, such as the Sacromaniacs and Wolfpac, have clashed with PENI members whom they view as both criminals and gangsters.

PENI members often tattoo themselves with numbers or letters that refer to the group.  Members may have tattoos that spell out Public Enemy Number 1 or simply their version of its initials, PENI.  They may also refer to other terms or acronyms for the group, including Pen1, Peni Death Squad, PDS and Pen9.  Peni Death Squad is just an alternate name for the group and does not signify the enforcers within the gang or a more violent sect within the organization.  The number most commonly associated with the group is 737, which refers to the letters PDS on telephone touch pads: 7=P, 3=D, 7=S.  Often these references appear among other racist and non-racist images, including common neo-Nazi tattoos, Viking imagery and Odinic symbols. Like many gang members, PENI tend to be heavily tattooed.