Leon is a crime boss who makes a one time appearance in the Season 2 episode titled "Random Target".
Leon is one of several crime bosses who is invited to the desert resort of George Dent to meet master criminal Kenneth Langhorn who has been in hiding overseas. The objective of the meeting is, as Dent puts it, "to divide up the United States" among them. Langhorn was to cement a new deal but Leon doesn't think Langhorn can handle the crime scene without the others. Leon and the other crime bosses own all the rackets in the United States. At most, Langhorn can run it for them. Langhorn pretends to agree, walks off and then orders his hitmen to kill all the crime bosses present, including Leon and George Dent. Later when Airwolf flew over the desert resort, Dominic remarks that "it's the St. Valentine's Day massacre all over again."