Martina Kostro
Head of Human Resources; Chief Human Resources Officer & Authorized Signatory
Experience
Head of Human Resources; Chief Human Resources Officer & Authorized Signatory
Clarius Group
- Established and led the Human Resources department for Clarius Group and its subsidiaries
- Supported the founding and development of Clarius Services GmbH (Managed Services Provider in Legal Tech, Compliance and Finance Operations), coached the team and provided strategic guidance
- Led change processes, set up new structures and standards, and integrated company acquisitions including cultural integration and team onboarding
- Built the HR team and took responsibility for HR strategy, recruiting, employee retention, employer branding and performance management
- Supported negotiations with large works council bodies
- Guided the digital transformation and implemented AI solutions in Legal Tech
- Developed and executed growth and scaling strategies, conducted market analysis and aligned the organization for sustainable growth
- Coached teams and leaders, promoted talent and established a new corporate culture
Interim Manager
Freelance Work
- Designed structures, processes and teams in growth and transition phases
- Advised and supported leaders and teams through complex change processes using coaching, sparring and organizational development
- Took on operational responsibilities, project management, process optimization and team leadership
- Ensured efficient, KPI-driven and sustainable structures
- Worked on three projects: a growth company in the crafts sector (buy-and-build strategies), an event management agency (succession planning and handover), and Clarius Group
Chief Operating Officer, HR; Co-Managing Director, E-Commerce & Performance Marketing
ameo GmbH
- Supported the change and transformation process of a fast-growing Amazon start-up on its path to becoming a grown-up
- Led a 40-person team and established stable structures, processes and clear responsibilities for sustainable scaling
- Combined leadership, coaching and organizational development with pragmatic implementation skills to boost performance
- Implemented standardized processes and optimized internal workflows
- Ensured collaboration between operational teams and strategic stakeholders
- Acted as the CEO's sparring partner: supported decision-making, developed new business areas and drove the transformation into a structured grown-up
Managing Director; Co-Managing Director
Heartbrands GmbH
- Redirected structures, processes and team dynamics after a change of management and the COVID-19 pandemic
- Combined strategy, operational leadership, business development and transformation
- Introduced flexible work models and redefined roles and responsibilities
- Evolved the team structure to strengthen efficiency, motivation and collaboration
- Developed comprehensive concepts along the employee life cycle for FMCG companies: recruiting, onboarding, performance management and offboarding
- Designed and supported employer branding campaigns to strengthen the employer brand and corporate culture
- Led and developed a team of around 15 employees through coaching, talent development and clear goal setting
Member of Management Board & Co-Shareholder
Medienpool Extra GmbH & HIW
- Shaped the company's business over 11 years as an entrepreneur
- Built and developed business areas, projects and teams
- Handled strategic planning, controlling and business development in the field of ambient media and out-of-home communication
- Led interdisciplinary project teams and coordinated external partners and sponsors
- Developed sustainable partnerships and long-term business relationships
Project Management; Project Leadership; Business Development
Medienpool Extra GmbH & HIW
- Set up and improved structures and processes at a media service provider for ambient and out-of-home communication
- Identified new business opportunities and expanded customer relationships strategically
- Managed a 20-person team
- Led large sports and cultural events from the initial idea to execution, including project management, budget responsibility, sponsorship, and marketing
- Coordinated with clients, partners, and public institutions
- Developed and grew the Ambient Media business unit: strategic planning, sales, creative implementation, and business development for the culture, leisure, and tourism sectors in northern Germany
Client Consulting & Business Development
Vasata Schröder Werbeagentur
- Responsible for new business and strategic client development after completing training
- Identified new business opportunities and contributed to the strategic direction of client projects
Intern & Trainee
Vasata Schröder Werbeagentur
- Helped build an owner-managed advertising agency from its founding
- Managed the major client Tengelmann (Plus Discounter) and acquired new clients
- Worked on pitches and in sales; received extensive sales training
- Developed skills in strategic client development, brand communication, and long-term relationship management
Industry Experience
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Experienced in Advertising, Media and Entertainment, Professional Services, Retail, Construction, and Manufacturing.
Business Area Experience
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Experienced in Project Management, Strategy, Marketing, Finance, Sales, and Human Resources.
Summary
I am an experienced generalist with over 20 years of leadership experience—ranging from micro businesses and mid-sized organizations to large corporations. I work flexibly, take on responsibility, quickly familiarize myself with new structures, and build trust with teams, managers and stakeholders through my open and appreciative manner. My strength is quickly grasping complex situations and implementing changes in a pragmatic and effective way. I am passionate about shaping change sustainably, seeing people in their best roles and leading teams to peak performance. With a strong hands-on mentality, I develop structures, processes and organizations with the goal of placing people in the right roles, unlocking their potential and sustainably increasing performance and productivity. Especially in times of skilled labor shortages, my focus is on making existing strengths within teams visible and using them purposefully to boost efficiency, motivation and satisfaction. I coach C-level executives and managers, guide teams through transformation processes and support organizations in building clear, solid and future-proof structures. A special focus of my work is effective conflict management—early detection of tensions, constructive handling of different interests and building clarity, trust and shared alignment. Empathy, clarity and a positive, motivating energy shape my way of working and enable me to lead organizations safely through dynamic phases.
Skills
- C-level Interim Management
- Coo
- Executive Management
- Hr
- Business Development
- Transformation
- Organizational Development
- Change Management
- Team Building
- Structure Building
- Process Optimization
- Digitalization
- Ai
- Hr Tech
- Martech
- Start-up
- Grown-up
- Scaling
- Outsourcing
- Flexibility
- Works Council Negotiations
- Outplacement
- Coaching
- Empathy
- Hands-on Mentality
- Leadership
- Motivation
- Team Leadership
- People & Operations
- Performance Improvement
- Employee Retention
- Change Facilitation
- Positive Energy
- Athleticism
- Dynamism
Languages
Education
Hochschule Wismar & Northern Business School
Diploma in Business Administration (FH) · Business Administration with a focus on Human Resources and Marketing · Wismar, Germany
Kommunikationsakademie Hamburg
Communications Specialist · Hamburg, Germany
Friedrich-Dessauer-Gymnasium Frankfurt am Main
German Abitur · Frankfurt, Germany
Certifications & licenses
Certified Business Coach
V.I.E.L. Coaching + Training Hamburg
Statistics
Experience
Expertise
Qualifications
Profile
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