David Kellner - Customer Service and Sales Director

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Dasing, Germany

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Experience

Mar 2024 - Present

2 years 6 months

Freelancer - Self-employed

David Kellner Consulting

Analyze existing structures and processes in customer service
Develop sustainable strategies to optimize service quality under current conditions
Implement efficient workflows and modern service concepts
Build a resilient service organization with flexible responsiveness to market changes
Ensure transparency through comprehensive process documentation, definition, and monitoring of relevant KPIs
Establish and actively shape the Digital Transformation area as an interface function between departments and IT
Lead the project 'Digitalization and Optimization of Processes in the Sales Back Office'
Introduce Power BI to increase transparency and data-driven control in the sales area
Contract management using the Zoho modules CRM/Sign/Contracts
Project management for SAP S/4HANA business migration

Sep 2023 - Feb 2024

6 months

Gersthofen, Germany

Head of Inside Sales

Humbaur GmbH

Lead, manage, and optimize the inside sales department (approx. 10 employees)
Sales controlling and forecasting
Define and map processes and KPIs in the SAP system landscape
Reporting line to Head of Sales

Jan 2013 - Jul 2023

10 years 7 months

Munich, Germany

Director Customer Service DACH

Rodenstock GmbH

Lead the Customer Service and Inside Sales division (80 customer service agents and service technicians, 8 teams at 7 locations)
Develop and implement the sales strategy
Continuously optimize business processes
Further develop KPIs
Reporting line to General Manager DACH

Mar 2008 - Dec 2012

4 years 10 months

Germany

Interim Sales Director

Rodenstock GmbH

Overall responsibility for the sales of Rodenstock products in Germany
Manage sales activities across all channels
Operational responsibility for key account management, field and inside sales, and customer service
Lead approx. 220 employees nationwide
Reporting line to CSO

Oct 2004 - Feb 2008

3 years 5 months

Germany

Project Manager Customer Relationship Management

Rodenstock GmbH

Project manager for global SAP CRM projects
International rollout of SAP CRM Mobile Sales for field sales, campaign management, and customer segmentation
Reporting line to Head of Pricing, Sales and Marketing Controlling

Aug 1998 - Sep 2004

6 years 2 months

Germany

Service Team Lead Regen/Munich

Rodenstock GmbH

Operational management and coordination of customer service teams and call centers in Bavaria
Managing around 30 employees
Reporting line to Head of Sales, Southern Region

Mar 1997 - Jul 1998

1 year 5 months

Germany

Quality Engineer

Rodenstock GmbH

Supporting manufacturing sites
Training managers
Conducting audits according to ISO 9000
Reporting line to Head of QM

Industry experience

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

Experienced in Manufacturing, Professional Services, and Automotive.

Manufacturing

Professional Services

Automotive

Business area experience

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

Experienced in Customer Service, Sales, Strategy, Operations, Project Management, and Information Technology.

Customer Service

Sales

Strategy

Operations

Project Management

Information Technology

Summary

Experienced senior manager with 28 years of professional experience in customer service, inside sales, sales management, and CRM project management, including in medical technology and optical industry
Solid experience in developing strategies, building and growing new business structures, and operational development of business processes and KPIs
Technical expertise in IT and strong commercial understanding
Development and implementation of strategic reorganization measures, as well as initiation and execution of change processes
Strong service and customer focus, result-oriented work style, independent and structured way of working, confident presence and closing skills, team player, communicator
Target areas: Customer Service, Inside Sales, Digital Transformation at senior management level

Skills

Microsoft Office 365
Sap Erp (Sd)
Sap Crm
Zoho Crm
Avaya Cie
Cognos
Qlikview
Power Bi
Family, Tennis, Skiing

Languages

German

Native

English

Intermediate

Education

Mar 1993 - Jan 1997

Fachhochschule Aalen

Diploma Engineer (FH) · Precision engineering, Optometry degree · Aalen, Germany

Jul 1991 - Jan 1993

Kellner & Schaller Optik OHG

Journeyman's certificate, Optician guild · Optician · Werl, Germany

Jun 1990 - Jun 1990

Städt. Marien-Gymnasium

High school diploma (Abitur) · Werl, Germany

Statistics

Experience

Total positions 7

Experience in Manufacturing 27 y

Avg length 4 y 1 m

Longest experience 10 y 6 m

Global experience

Countries worked in 1 (Germany)

Primary country Germany

Expertise

Recent roles Freelancer - Self-employed, Head of Inside Sales, Director Customer Service DACH

Main industries Manufacturing, Professional Services, Automotive

Main business areas Customer Service, Sales, Strategy

Qualifications

Highest degree Bachelor

Profile

Member since

February 2026

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Frequently asked questions

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David is based in Dasing, Germany and can operate in on-site, hybrid, and remote work models.

David speaks the following languages: German (Native), English (Intermediate).

David has at least 29 years of experience. During this time, David has worked in at least 7 different roles and for 3 different companies. The average length of individual experience is 4 years and 2 months. Note that David may not have shared all experience and actually has more experience.

Based on recent experience, David would be well-suited for roles such as: Freelancer - Self-employed, Head of Inside Sales, Director Customer Service DACH.

David's most recent position is Freelancer - Self-employed at David Kellner Consulting.

In recent years, David has worked for David Kellner Consulting, Humbaur GmbH, and Rodenstock GmbH.

David is most experienced in industries like Manufacturing, Professional Services, and Automotive.

David is most experienced in business areas like Customer Service, Sales, and Strategy. David also has some experience in Operations, Project Management, and Information Technology.

David has recently worked in industries like Manufacturing, Professional Services, and Automotive.

David has recently worked in business areas like Customer Service, Sales, and Strategy.

David holds a Bachelor in Precision engineering, Optometry degree from Fachhochschule Aalen.

David is immediately available part-time for suitable projects.

Daily rate distribution

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<€720 €720-800 €800-880 €880-960 €960-1040 €1040-1120 €1120+

The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.

Average rates for similar positions

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Daily rate avg. 874 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

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Median rate 840 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Calculated based on our freelancers’ daily rates as of 24 Aug 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.