John Allan has assisted clients in addressing state and local taxes for 21 years. He has handled tax matters in almost all of the 50 states. In addition, he assists clients in addressing state and local tax issues related to corporate reorganizations. He regularly represents clients before state tax agencies and in proceedings before the Multistate Tax Commission.

He has advised clients in the manufacturing, transportation, financial services, telecommunication, hospitality, distribution, and retail industries.

John previously served as editor-in-chief of the American Bar Association's State and Local Tax Lawyer. He is former chair of the Georgia Department of Revenue's Advisory Committee and of the Southeastern Association of Tax Administrators (SEATA) Advisory Council. John is the immediate past chair of the State Bar of Georgia Tax Section. John also chaired the Georgia Bar Tax Section's Tax Court Task Force, which was instrumental in the enactment of legislation creating Georgia's Tax Tribunal in the 2012 Georgia Legislative session.

John speaks frequently on state and local tax matters before such groups as the Council on State Taxation, the Institute for Professionals in Taxation, the Tax Executives Institute (TEI), the Federation of Tax Administrators, and SEATA. Articles coauthored by John and published in The State and Local Tax Lawyer include: "Commerce Clause Implications of Locally Imposed Gross Receipts Based Taxes," Vol. 8, 2003; "Defending Against a Geoffrey Assessment: Statutory Problems Inherent in Economic and Intangible Based Nexus Theories," Vol. 3, 1998; and "The Extraterritorial Assertion of State Taxing Power: Onward to the Past," Vol. 2, 1997.