Leon Walsh is a successful husband, father, and businessman? who happens to be embattled in a deadly, Northern California turf war with the Cartel.

No need to mention the main character's name and better to shrink his description to less words such as When a father of three is or when a successful business man or when a loving family man.

In a good story there is no such thing as "...happens to be..." there are tailor made characteristics and events made to put the MC in the worst possible position for him or her to fight there way out of. better to describe the event that forces the MC to do battle with the antagonist.

I gather "...the Cartel." is the antagonist but the description lacks specificity. By using the definite article "...the..." you imply the reader knows of the cartel but no information was given prior. Better to add an adjective and ideally let it describe the type of antagonist the MC will be up against. For example: sadistic drug-cartel, human trafficking cartel, illegal organ harvesting cartel... etc.

Hope this helps.