Doyle was born in Swissvale, Pennsylvania and graduated from Penn State in 1975 with a degree in Community Development. Doyle worked in the steel mills during his time in college. After college he worked as an insurance agent and was elected to the Swissvale Borough Council in 1977. In 1978 he worked as chief of staff to Pennsylvania State Senator Frank Pecora. Like his mentor Pecora, Doyle was once a Republican who later switched parties to become a Democrat.

In 1994, Doyle was elected to the House of Representatives as a Democrat. He filled the seat of now-U.S. Senator Rick Santorum.

In 2002 Doyle’s district was combined with the Pittsburgh-based district of former Congressman William J. Coyne. The potentially explosive situation of having two Democratic incumbents face each other in the primary was defused when Coyne announced his retirement (even though the district contained more of Coyne's former territory than Doyle's) leaving Doyle as the sole incumbent. Doyle faced no general election opposition in 2002 and 2004 in this overwhelmingly Democratic district.

Doyle is considered one of the more moderate Democrats in the House. He opposes abortion, supported a constitutional amendment prohibiting flag desecration, and supported a bill limiting federal death penalty appeals. He has also supported "left wing" issues including voting against authorizing military force in Iraq and against the $87 Billion emergency spending bill to fund US troops in Iraq and Afghanistan.

During his time on Congress, Doyle has served on the Veterans' Affairs Committee, the Science and Technology Committee, and the Energy and Commerce Committee. He is also one of five Democrats serving on the House Ethics Committee.