Located in the heart of Irvine’s central business district, Withum is one of the nation’s top-rated accounting firm. Withum helps local corporations and nonprofits thrive, offering advisory, tax, audit, assurance and management consulting services to the Orange County business community.
Find Our Orange County Office
100 Spectrum Center Drive
Suite 1000
Irvine, CA 92618
Phone: (949) 261-0808
Partner-in-Charge: Ken Johnson
Orange County Industry Specializations
Healthcare
Learn moreFinancial Services
Learn moreNot-For-Profit
Learn moreTechnology
Learn moreLife Sciences
Learn moreConstruction
Learn moreManufacturing
Learn moreWithum in the Community
Community involvement and volunteering are integral to Withum’s Orange County office and overall company culture. We are dedicated to SoCal through community involvement, and our team is so proud to serve on the boards of non-profit organizations, participate and contribute to local fundraisers and mentor future generations throughout the year.
Beyond the Orange County Office
- Inside Public Accounting Top 100 Firms - 23rd Largest Nationally
- Accounting Today Top 100 Firms - 22nd Largest Nationally
- Great Place to Work® – Fortune Best Workplaces for Parents and Women
- Vault Top 25 Accounting Firm
Partner In Charge

Ken bringsnearly threedecades ofexpertisein conducting audits and reviews for both privately held and publicly traded companies.
In addition to his successful career working with and advisingthe firm’sclients, Ken dedicates much of his time to non-client-focused activities, such asthe daily operations andpeople strategy of the Orange County office and its growth in the local marketplace.