Mike Piper spent 28 years working on the city's tax system as head of the Office of Property Assessment.
Finance Director Rob Dubow praised his work ethic and his commitment to taxpayer services, but he was frequently under fire by City Council for what some members considered stealth tax increases in the form of skyrocketing assessments for residential real estate.
Commercial property owners, meanwhile, successfully sued the city over their assessments.
A judge ordered the city and School District of Philadelphia to return $48 million in revenue from increased assessments, an order that the city has appealed to Commonwealth Court.
The city decided not to do reassessments this year because of concerns about mistakes in the process.
A new computer-assisted appraisal will be launched in the spring.