Davis was a 1994 graduate of Tuscaloosa County High School and worked at the Parkview Drug Store in Tuscaloosa out of high school. He earned his bachelor of arts in criminal justice and psychology at the University of Alabama in 2000 and joined the campus police. After four years in Dallas, Texas he returned to Alabama to join the Calera Police Department.
In 2005 he completed a master of science in criminal justice at Faulkner University and joined the Pelham force, where he acted as field training officer and evidence technician. He also taught self-defense classes at Valley Christian Church and criminal justice classes at ITT Technical Institute in Bessemer and Herzing College. He and his wife, Paula, a Drug Enforcement Agency employee, had a daughter, Sarah Katelyn, and a son, John Archimedes.
Just before midnight on December 3, Davis pulled over pharmacist Bart Wayne Johnson for speeding on I-65 near the "tank farm" at mile marker 243. The traffic stop was captured on video from a camera in Davis' patrol car. After a seemingly calm interview, Davis returned to his patrol car to write a ticket. When he returned, Johnson informed him that his brother was a police officer. Davis asked for his contact information so he could tell him what happened. Then Johnson pulled a handgun and shot Davis in the face. He was taken to UAB Hospital where he was pronounced dead. He was the first Pelham officer to die in the line of duty in the department's 45-year history.
Johnson fled the scene and was later observed attempting to break into a pick-up truck in Birmingham's Inglenook neighborhood. He waved a resident back into his house by flashing his gun. The resident later observed Johnson's brother, Bill, a Trussville police officer, pick him up in his truck. The two drove toward Pelham, apparently to surrender, but stopped when they saw a large group of Hoover Police cars near an I-65 interchange with U. S. Highway 31. They stopped and got out of the car with their hands in the air. Bart Johnson announced that he was the subject of their manhunt. Both brothers were taken into custody. Bart Johnson was later charged with capital murder and held without bond. A grand jury indicted him on separate charges of intentionally killing an on-duty police officer and intentionally causing a death by shooting from an occupied vehicle on December 10. The state announced it would seek the death penalty on both charges. Johnson pleaded not guilty at a March 4 hearing.
A Philip Davis Fund was created at America's First Credit Union to support his family. Davis' funeral was held at the Church at Brook Hills on December 8 with burial taking place at Southern Heritage Funeral Home in Pelham afterward. Flags in Pelham were flown at half-staff in Davis' honor. Davis' family was able to pay off their mortgage with the donations, and a mortgage-burning ceremony was held at Pelham Civic Complex in April 2010.
Johnson was found guilty of two counts of capital murder on May 12, 2011 by a Shelby County jury, who recommended the death sentence. Johnson's plea of not guilty by reason of mental default was rejected by the jury. Judge Al Crowson set sentenced Johnson to death at a June 16 hearing.
The City of Pelham renamed Church Street, behind the Pelham City Hall and the location of the Pelham Police Headquarters, in honor of Davis. The Alabama Department of Transportation also dedicated a section of I-65 where he was killed the "Philip Davis Memorial Highway".
- Robinson, Carol (December 5, 2009) "Pelham police officer's slaying baffles investigators." The Birmingham News
- Phillips, Austin (December 6, 2009) "Funeral arrangements set for fallen Pelham police officer." Shelby County Reporter
- "Philip Mahan Davis" obituary. (December 6, 2009) The Birmingham News
- Phillips, Austin (December 7, 2009) "Community pays its respect to slain officer." Pelham Reporter.
- Wagner, Neal (December 10, 2009) "State seeking death penalty against man charged with killing police officer." Shelby County Reporter
- Davis, Paul (December 13, 2009) "One question remains at time of tragedy: ‘Why, dear Lord?’" Opelika-Auburn News
- Phillips, Austin (March 25, 2010) "City of Pelham plans mortgage-burning ceremony for Davis family." Shelby County Reporter
- Daniels, Malcomb (May 13, 2011) Shelby County jury recommends death for Pelham cop killer Bart Wayne Johnson." The Birmingham News
- Daniels, Malcomb (June 16, 2011) "Bart Wayne Johnson sentenced to death for killing Pelham police officer." The Birmingham News
- Wagner, Neal (December 9, 2014) "We will never forget." Shelby County Reporter