Pileggi was born in Chester, Pennsylvania and graduated from Archmere Academy, a private Roman Catholic college preparatory school located in Claymont, Delaware.

Pileggi ran in a special election on October 1, 2002 to fill the seat of State Senator Clarence Bell, who died on July 26, 2002.

[9] After the shakeup in leadership caused in part by the 2005 legislative pay raise, Pileggi was elected by his colleagues to serve as the Republicans' floor leader in November 2006.

"[14] In the 2007-08 legislative session, Pileggi was the prime sponsor of Senate Bill 1, which rewrote Pennsylvania's Open Records Law for the first time in more than 50 years.

"[16] Pileggi was the prime sponsor of Senate Bill 1100, which transferred approximately $17 million to Pennsylvania's Hazardous Sites Cleanup Act (HSCA) Fund out of legislative accounts, ensuring that the HSCA Fund could meet its obligations in the 2007-08 fiscal year.

[18] In November 2015, Pileggi was one of three individuals elected to serve as a Judge on the Pennsylvania Court of Common Pleas in Delaware County.