Prizzi's Family — Richard Condon

In this prequel to Prizzi's Honor, the mafia hitman finds himself in more trouble than even he can handle -- “earthy, quirky, fast-moving entertainment” (Kirkus Reviews, starred review).

Charley Partanna sits in his office, quietly rigging an election. As the chief executioner for the Prizzi family, he has taken time out of his busy schedule of cold-blooded murder to ensure that New York reelects its mayor, and that dirty money continues to flow his way. When he isn't killing snitches or stealing votes, Partanna goes to night school, but tonight, his homework will have to wait. The Prizzis are going to war.
 
For Partanna, a mob war is nothing but an inconvenience. The streetwise underboss can make a hit completely undetected. But when he makes the mistake of falling in love with the don's granddaughter, Partanna will see just what kind of trouble the Prizzi family can cause.
 
Prizzi's Family is the 2nd book in the Prizzi series, but you may enjoy reading the series in any order.