It was unclear on Thursday whether the driver, described as being between 25 and 40 years old, struck Mr. Cali’s vehicle to lure him outside, or whether the two men knew one another.

The bloody attack, in some ways, did not bear the hallmarks of hits from the past. Mafia hit men once considered it taboo to kill a rival at his home, near his family. It was also unusual in previous eras for a single gunman, rather than a team, to execute a high-ranking mobster.

And yet, even against its serene setting on Hilltop Terrace, with its stately homes, circular driveways and swimming pools, the image of Mr. Cali’s body lying on the street was a throwback to the black-and-white photographs of Mafia assassinations past.

[Todt Hill, a getaway from the bustling city, offers privacy that has appealed to mob bosses.]

The last time the boss of a Mafia family was assassinated was in 1985. The former Gambino boss Paul Castellano was gunned down outside Sparks Steak House in Midtown, a power grab orchestrated by a young Mr. Gotti, who ran the family through the late 1980s in his trademark showy style.

Mr. Cali rose quickly through the ranks of the family, becoming a “made” member in the late 1990s, on the way to a “swift promotion” to acting captain in less than 10 years, a prosecutor, Joey Lipton, said at a 2008 detention hearing after Mr. Cali’s arrest in an extortion case. In Federal District Court in Brooklyn, Mr. Lipton said Mr. Cali had “familial and blood ties” to the Gambino family, tracing back to Sicily.

His wife, Rosaria Inzerillo, had several relatives associated with the Gambino family, including her cousin, Tommy Gambino, court papers from that hearing said. Mr. Cali started out in a crew under a rising captain, John D. D’Amico, known as Jackie the Nose, who became the acting boss of the family around 2005.