Katari Y. Villanueva

Accomplished Strategic Executive Assistant and Operations Leader with over 15 years of progressive experience providing high-level C-Suite support, driving operational excellence, and fostering cross-functional collaboration within complex corporate environments. Recognized as a dedicated mentor and trusted advisor with a proven track record of managing sophisticated executive calendars, coordinating complex projects, and streamlining business workflows. A passionate champion for workplace culture who excels at onboarding administrative staff, mentoring emerging leaders, and bridging the gap between executive strategy and daily staff execution.

Bilingual professional dedicated to maintaining absolute confidentiality, service excellence, and team empowerment.

Senior Client Service Executive | Strategic Executive & Operations Support at MOUNT SINAI HEALTH SYSTEM – FACULTY PRACTICE ADMINISTRATION (2021-09 – 2026-05)

• Partnered directly with executive leadership, multi-service line directors, and business stakeholders to execute strategic corporate initiatives and resolve complex operational challenges.
• Managed complex schedules, facilitated high-level committee meetings, tracked project milestones, and ensured timely execution of executive action plans.
• Developed executive reports, dynamic dashboards, and presentations utilizing Tableau and Excel to guide C-Suite decision-making.
• Coordinated corporate onboarding programs and provided direct administrative support for incoming organizational leaders and stakeholders.
• Conducted root-cause analysis on operational data to identify efficiency gaps and implement corrective administrative workflows.
• Mentored administrative staff and actively participated in high-level organizational steering committees to drive workplace culture.
• Elevated administrative efficiency across multiple departments through workflow optimization and clear communication frameworks.
• Successfully managed critical, high-profile corporate accounts and complex operational projects under tight deadlines.

Billing Manager & Administrative Supervisor (Par & Non-Par Teams) at MOUNT SINAI HEALTH SYSTEM – FACULTY PRACTICE ADMINISTRATION (2016-04 – 2021-09)

• Directed daily operations and administrative workflows for multi-tiered teams handling high-volume financial portfolios.
• Handled complex calendar coordination, workload distribution, resource management, and administrative staffing plans for multiple departments.
• Managed high-level relationships with corporate vendors, legal representatives, and external business partners to resolve escalated disputes.
• Led, trained, and mentored supervisors and administrative staff through formal coaching, performance evaluations, and skill development.
• Audited internal workflows to ensure rigid regulatory compliance, data integrity, and operational excellence.
• Facilitated recurring department-wide meetings to align staff with changing corporate objectives and organizational priorities.

Assistant Manager – Orthopedics Department at MOUNT SINAI BETH ISRAEL (2014-10 – 2016-04)

• Managed daily departmental operations, administrative workflows, and facility logistics for a busy medical division.
• Supervised, trained, and onboarded administrative employees while promoting an office culture of productivity and service excellence.
• Managed multi-party communications between providers, corporate leadership, patients, and external regulatory organizations.
• Generated operational trend reports to directly support executive management decisions and special projects.

Data Specialist – Women's Health / OB-GYN at MOUNT SINAI BETH ISRAEL (2011-09 – 2014-10)

• Maintained critical enterprise data arrays and generated complex operational performance metrics.
• Spearheaded database reconciliation, audit tracking, and cross-departmental administrative alignment.

Pre-Registration Specialist / Trainer at ST. JOSEPH MEDICAL CENTER (2009-09 – 2011-09)

• Provided elite customer service while managing patient accounts, scheduling configurations, and complex documentation.
• Personally trained and mentored all incoming administrative employees on corporate systems and client service standards.

High School Diploma – Enterprise Business and Technology