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Martina Kostro

Head of Human Resources; Chief Human Resources Officer & Authorized Signatory

Martina Kostro
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Hamburg, Germany

Experience

Apr 2025 - Present
1 year

Head of Human Resources; Chief Human Resources Officer & Authorized Signatory

Clarius Group

Expertise details
Position Summary
Head of Human Resources; Chief Human Resources Officer & Authorized Signatory at Clarius Group
Industries
Information Technology
Professional Services
Business Areas
Human Resources
  • 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
Sep 2024 - Present
1 year 7 months

Interim Manager

Freelance Work

Expertise details
Position Summary
Interim Manager at Freelance Work
Industries
Construction
Manufacturing
Media and Entertainment
Professional Services
Business Areas
Operations
Project Management
Strategy
  • 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
Oct 2022 - Aug 2024
1 year 11 months

Chief Operating Officer, HR; Co-Managing Director, E-Commerce & Performance Marketing

ameo GmbH

Expertise details
Position Summary
Chief Operating Officer, HR; Co-Managing Director, E-Commerce & Performance Marketing at ameo GmbH
Industries
Professional Services
Retail
Business Areas
Human Resources
Marketing
Operations
  • 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
Sep 2021 - Sep 2022
1 year 1 month

Managing Director; Co-Managing Director

Heartbrands GmbH

Expertise details
Position Summary
Managing Director; Co-Managing Director at Heartbrands GmbH
Industries
Professional Services
Business Areas
Human Resources
Marketing
Strategy
  • 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
Jan 2010 - Aug 2021
11 years 8 months

Member of Management Board & Co-Shareholder

Medienpool Extra GmbH & HIW

Expertise details
Position Summary
Member of Management Board & Co-Shareholder at Medienpool Extra GmbH & HIW
Industries
Advertising
Business Areas
Finance
Project Management
Strategy
  • 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
Jan 2005 - Dec 2009
5 years

Project Management; Project Leadership; Business Development

Medienpool Extra GmbH & HIW

Expertise details
Position Summary
Project Management; Project Leadership; Business Development at Medienpool Extra GmbH & HIW
Industries
Media and Entertainment
Business Areas
Marketing
Project Management
Sales
  • 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
Sep 2002 - Dec 2004
2 years 4 months

Client Consulting & Business Development

Vasata Schröder Werbeagentur

Expertise details
Position Summary
Client Consulting & Business Development at Vasata Schröder Werbeagentur
Industries
Advertising
Business Areas
Marketing
Sales
Strategy
  • Responsible for new business and strategic client development after completing training
  • Identified new business opportunities and contributed to the strategic direction of client projects
Jan 2000 - Sep 2002
2 years 9 months

Intern & Trainee

Vasata Schröder Werbeagentur

Expertise details
Position Summary
Intern & Trainee at Vasata Schröder Werbeagentur
Industries
Advertising
Business Areas
Marketing
Sales
  • 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

See where this freelancer has spent most of their professional time.

Experienced in Advertising, Media and Entertainment, Professional Services, Retail, Construction, and Manufacturing.

Advertising
Media and Entertainment
Professional Services
Retail
Construction
Manufacturing
Profile match chart

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Project Management, Strategy, Marketing, Finance, Sales, and Human Resources.

Project Management
Strategy
Marketing
Finance
Sales
Human Resources
Profile match chart

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

German
Native
Croatian
Native
English
Advanced
French
Elementary

Education

Sep 2009 - Sep 2013

Hochschule Wismar & Northern Business School

Diploma in Business Administration (FH) · Business Administration with a focus on Human Resources and Marketing · Wismar, Germany

Sep 2000 - Sep 2002

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

Total positions 8
Experience in Advertising 16.5 y
Avg length 3 y 4 m
Longest experience 11 y 7 m

Expertise

Recent roles Head of Human Resources; Chief Human Resources Officer & Authorized Signatory, Interim Manager, Chief Operating Officer, HR; Co-Managing Director, E-Commerce & Performance Marketing
Main industries Advertising, Media and Entertainment, Professional Services
Main business areas Project Management, Strategy, Marketing

Qualifications

Highest degree Bachelor
Certifications earned 1

Profile

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Martina based?

Martina is based in Hamburg, Germany.

What languages does Martina speak?

Martina speaks the following languages: German (Native), Croatian (Native), English (Advanced), French (Elementary).

How many years of experience does Martina have?

Martina has at least 26 years of experience. During this time, Martina has worked in at least 8 different roles and for 6 different companies. The average length of individual experience is 3 years and 3 months. Note that Martina may not have shared all experience and actually has more experience.

What roles would Martina be best suited for?

Based on recent experience, Martina would be well-suited for roles such as: Head of Human Resources; Chief Human Resources Officer & Authorized Signatory, Interim Manager, Chief Operating Officer, HR; Co-Managing Director, E-Commerce & Performance Marketing.

What is Martina's latest experience?

Martina's most recent position is Head of Human Resources; Chief Human Resources Officer & Authorized Signatory at Clarius Group.

What companies has Martina worked for in recent years?

In recent years, Martina has worked for Clarius Group, Freelance Work, ameo GmbH, Heartbrands GmbH, and Medienpool Extra GmbH & HIW.

Which industries is Martina most experienced in?

Martina is most experienced in industries like Advertising, Media and Entertainment, and Professional Services. Martina also has some experience in Retail, Construction, and Manufacturing.

Which business areas is Martina most experienced in?

Martina is most experienced in business areas like Project Management, Strategy, and Marketing. Martina also has some experience in Finance, Sales, and Human Resources.

Which industries has Martina worked in recently?

Martina has recently worked in industries like Advertising, Professional Services, and Retail.

Which business areas has Martina worked in recently?

Martina has recently worked in business areas like Strategy, Project Management, and Finance.

What is Martina's education?

Martina holds a Bachelor in Business Administration with a focus on Human Resources and Marketing from Hochschule Wismar & Northern Business School.

Does Martina have any certificates?

Martina has 1 certificate: Certified Business Coach.

What is the availability of Martina?

Martina will be available from April 2026.

What is the rate of Martina?

Martina's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.

How to hire Martina?

To hire Martina, click the Meet button on the profile to request a meeting and discuss your project needs.

Average rates for similar positions

Rates are based on recent contracts and do not include FRATCH margin.

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Market avg: 680-840 €
The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.
Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.