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Meet our Team

Mark Schou, CPA

Mark serves as the firm’s managing partner and has over 27 years of experience in both private industry and public accounting. In 1994, he merged his public accounting firm with two of the firm’s founding partners, Ben Cornelius and Andy Culpepper. Mark’s areas of focus include design of business and tax structures, start-up, mergers and acquisitions of privately held companies and tax and business advisement in both the United States and Mexico.

Mark is a native of Jacksonville and is actively involved in the Jacksonville community. He is currently serving, or has served, on a variety of committees and boards of directors including: The Leukemia Society of America, International Resource Center of Jacksonville, Mental Health Resource Center, Inc., Department of Health and HRS – Rotary Club of Jacksonville, Pop Warner Youth Football, The Terry Parker High School Alumni Fund and Deermeadows Baptist Church. Mark is also an active member in the American Institute of Certified Public Accountants the Florida Institute of Certified Public Accountants and CPA USA Association.

Upon graduation from Terry Parker High School in 1982, Mark attended the University of Tennessee at Chattanooga where he played collegiate football for two years before returning to Jacksonville to complete his Bachelor of Business Administration in Accounting from the University of North Florida. He later received his Master of Science Degree in Business from the University of Miami. He is a licensed Certified Public Accountant in the State of Florida.

John, “Jack” Leone, CPA

Jack has over 28 years of experience in accounting, 23 of those years in private practice. Jack’s areas of focus include automobile dealers, contractors, restaurants and franchises and home owners associations. He also has extensive experience in personal and business tax / accounting matters.

Jack is a native of Boston but began calling Jacksonville home in 1985. He is actively involved in the Jacksonville community serving on a variety of committees and boards of directors including: St. Joseph’s Catholic Church, Alliance for the Lost Boys of Sudan and The Harvey Bernhardt Foundation. He is an active member in the American Institute of Certified Public Accountants, Florida Institute of Certified Public Accountants, and the Affordable Housing Association of Certified Public Accountants.

Upon graduation from high school in 1981, Jack attended the University of Maine where he received his Bachelor of Business Administration in Accounting. Jack was a four-year starter on the University of Maine Black Bears 1-AA collegiate football team and still and holds the record as the school’s all-time leading scorer. Jack also attended the University of North Florida where he obtained his requirements to become a CPA in the State of Florida. Jack is a licensed Certified Public Accountant in both Florida and Massachusetts.

Walter Johnston, CPA

Walter has over 33 years of experience in accounting, 30 of those years in private practice. Walter’s areas of focus include For Profit and Non-Profit Audits and tax / IRS reporting as well as taxation of closely held businesses and their owners. He also has extensive experience in Governmental Audits and reporting and Single Audit compliance and reporting.

Walter is a native of Tifton, Georgia but began calling Jacksonville home in 1984. He is actively involved in the American Institute of Certified Public Accountants, the Florida Institute of Certified Public Accountants and various ministries of Chets Creek Church.

Upon graduation from high school in 1977, Walter attended Valdosta State University where he received his Bachelor of Business Administration in Accounting.  Walter is a licensed Certified Public Accountant in the State of Florida.

Sonja Cvijanovic, CPA

Sonja is originally from Serbia.  With hopes of a better future, Sonja left Serbia in 2009 and put herself through school in Jacksonville.  She joined CS&L after completing her Bachelor of Business Administration in Accounting at University of North Florida in 2014 and has since become a crucial member of our team.

Upon passing the CPA exam, Sonja enrolled in Florida State University where she is pursuing licensure in its Management Information Systems Master’s program.  She speaks four languages and prepares taxes in all of them.

As your ally in matters with the IRS, Sonja will actively fight your tax battles.  Her motto, “be audit you can be” also keeps her actively involved in Jacksonville’s Chamber of Commerce and the Florida Institute of Certified Public Accountants .  When Sonja is not advocating for your positive tax outcome, she enjoys photography and going to the beach to clear her mind.

Alyssa Byrne, Staff Accountant

Alyssa was born and raised in Orange Park where she attended Orange Park High School.  While actively involved in Future Business Leaders of America, she identified her dream to become an accountant.

Alyssa studied at University of North Florida where she obtained a Bachelor of Business Administration in Accounting in 2015.  Soon thereafter, she joined CS&L with a focus in Corporate Accounting.  She is a member of ImpactJax and is currently working toward her CPA license.

When she is not crunching numbers, Alyssa enjoys riding her horse, Vera, in competitions and for fun.

Peter Cotroneo, Staff Accountant

Originally from White Plains, NY, Peter moved to Florida at a young age because his parents were ready to trade the snow for sunshine. He has been a resident of Florida ever since. After attending Bartram Trail High School, Peter moved south to Boca Raton, where he attended Florida Atlantic University. Knowing that accounting was in his future, he applied and was accepted into the Accounting Scholars Program (ASP). The ASP is an honors program designed to help students achieve a high level of proficiency in the skills useful to this industry. In addition to his studies, Peter was involved in Beta Alpha Psi International Honor Society where he enhanced his leadership skills taking on an officer position.

Peter graduated from FAU in 2018 with a Bachelor of Business Administration in Accounting. He moved back home to Jacksonville and is the newest addition to the CSL Family. If you can’t find him in the office, he’s out enjoying a round of golf with clients.

Ben Cornelius, CPA

After 30 years in public accounting, Ben retired from full-time practice in 2007.  Ben’s expertise includes trusts, estate planning and personal income and business tax planning. He holds a BA in business administration from Belmont Abbey College and is a licensed CPA in the state of Florida.

He continues to be available as necessary. Ben is a co-founder of the firm.

Andy Culpepper, CPA

After 25 years in public accounting, Andy retired from full-time practice in 1997. He continues to be available to his former clients as necessary. Andy still helps us during the busy filing season. Andy is a co-founder of the firm.  He holds a MA and BA in accounting from the University of Georgia and is a licensed CPA in the state of Florida.