About our firm

Sonja Campbell is the owner of Cornelius, Leone & Campbell and a certified public accountant with more than 11 years of public accounting experience. She takes a proactive, advisory-focused approach, helping clients address both their immediate accounting needs and their long-term business objectives. She works primarily with small and midsize businesses, including construction contractors, restaurants, nonprofit organizations, and medical practices, and serves both domestic and international clients.

Her practice includes tax planning and compliance for individuals, businesses, trusts, estates, and gift-tax matters, as well as compilations, reviews, and audits for businesses requiring CPA-prepared or attested financial statements. She also provides strategic guidance on entity selection and structuring, succession planning, and business transitions, together with bookkeeping and financial statement preparation.

Originally from Serbia, Sonja came to the United States in 2009 and earned her Bachelor of Business Administration in Accounting from the University of North Florida in 2014. She joined the firm immediately after graduation and, after more than a decade with the firm, became its owner in November 2025.

Sonja also holds a master’s degree in management information systems from Florida State University. She is a member of the American Institute of Certified Public Accountants and the Florida Institute of Certified Public Accountants and is involved with the STXBP1 Foundation. Outside the office, she enjoys hiking, photography, and traveling with her family.

Jack has over 34 years of experience in accounting, 29 of those years in private practice. His areas of focus include automobile dealers, contractors, restaurants and franchises, and homeowners associations, as well as personal and business tax and accounting matters.

A native of Boston, Jack has called Jacksonville home since 1985. He is actively involved in the community through St. Joseph's Catholic Church and the Harvey Bernhardt Foundation, and is a member of the American Institute of Certified Public Accountants and the Florida Institute of Certified Public Accountants.

Jack received his BBA in Accounting from the University of Maine, where he was a four-year starter on the football team and still holds the record as the school's all-time leading scorer. He is a licensed CPA in both Florida and Maine.

Ben co-founded the firm in 1979 and spent 30 years in public accounting before stepping back from full-time practice in 2007. His areas of expertise included trusts, estate planning, and personal income and business tax planning.

He holds a BA in Business Administration from Belmont Abbey College and remains a licensed CPA in the state of Florida. Ben continues to be available as needed.