Tonianne has more than 30 years of experience practicing employment and labor law. Tonianne represents employers in a wide variety of industries including non-profit, health care, financial services, defense contractors, media, and education organizations. Tonianne takes pride in having partnered with many of her clients for over 25 years to assist them with resolving complex employment issues to satisfy business objectives and comply with legal requirements.

Tonianne has considerable experience in conducting workplace investigations involving a wide variety of issues, including harassment, discrimination, ethics violations and workplace theft. She often presents her results to Boards of Directors or General Counsels along with outcome recommendations.

A substantial portion of Tonianne’s practice involves counseling employers on a day-to-day basis on ways to navigate difficult business decisions such as terminating long-term employees, responding to harassment complaints; advising on challenging grievance issues, managing leaves of absence and preparing for reductions in force or other changes in the workplace. Given the significant costs of litigation, Tonianne is an advocate of preventive measures including strategic planning, proactive training, and customized policies. When litigation arises or is threatened, Tonianne often counsels clients on a range of responses, including alternative dispute measures.

Tonianne began her career clerking for The Honorable Lawrence W. Pierce on the Court of Appeals for the Second Circuit.  She thereafter joined the Labor and Employment Group of Simpson Thacher & Bartlett LLP, where she spent more than twelve years advising clients and litigating employment matters. From her role as Counsel at Simpson Thacher, Tonianne joined Collazo, Florentino & Keil LLP as a partner and continued her practice of representing employers on all aspects of labor and employment law.