| 1846 | Founding of the company by Hermann Bernhard Seissenschmidt. Production of railroad components, railroad car fittings, screws, bolts and nuts. |
| 1858 | Steam engines replace water power. |
| 1860 | Following the death of the company founder, his son Wilhelm Seissenschmidt takes over the leadership of the company. |
| 1882 - 1891 | Introduction of electric motors. Expansion of the company site and addition of 14 drop hammers in the forge. |
| 1893 | Establishment of a company health fund, construction of company housing, donation of charitable housing and a hospital to the city of Plettenberg. |
| 1901 | After the death of Wilhelm Seissenschmidt his widow, Eleonore, takes over the company leadership, followed in 1917 by their daughter, Anna Engelhard, wife of Medical Counsellor, Dr. Adolf Engelhard. |
| 1924 | Change of the corporate form into a family-owned stock company, H. B. Seissenschmidt AG. |
| 1928 | Egenolf Engelhard, great grandson of the company founder, takes over the leadership of the company. Founding of the “Medical Counsellor Dr. Adolf Engelhard Foundation” (Sanitätsrat-Dr.-Adolf-Engelhard-Stiftung) for supporting sick and needy employees or surviving dependents. |
| 1933/ 1934 | Expansion of the company by building a modern forging production site. |
| 1948 | Re-start of production: fasteners for heating radiators. |
| 1964 - 1976 | Investment in the first multi-stage press and commencement of production for forged parts supplied to the automotive industry. Transfer of the company to the Koebbinghausen industrial area |
| 1993 - 1995 | Restructuring from a conventional forge to a fully automatic forging company under the leadership of Hans-Dieter Gödeke. |
| 1999 | Rüdiger Groos and Hermann-Josef Müller join the company board of directors. |
| 2001 | Change of name to SEISSENSCHMIDT AG and construction of a new logistics center. Founding of SEISSENSCHMIDT Corporation in the US. |
| 2002 | Construction of a new production hall and a training and conference center. |
| 2004 | With the investment in a multi-stage press of the type AMP 70 XL HFE, SEISSENSCHMIDT is now equipped with a range of fully-automatic multi-stage presses that is unique worldwide. At the same time, extensive investments in machining mean that the number of parts supplied as ready-for-assembly components is continuing to increase. |
| 2006 | Founding of SEISSENSCHMIDT Components Processing GmbH + Co. KG, which is specialized in machining processes. SEISSENSCHMIDT once again expands its unique range of fully automatic multi-stage presses by investing in an HM 75 XL. |
| 2007 | Founding of the subsidiary SEISSENSCHMIDT Precision Components Kft. in Hungary. Transfer of conventional hot forging to the new production site. Building of a production site for the SEISSENSCHMIDT Corporation in Oscoda in the state of Michigan, USA. |
| 2008 | SEISSENSCHMIDT Components Processing GmbH + Co. KG undergoes expansion with the construction of a new machining site. Acquisition of the heat-treatment company Reitz GmbH & Co. KG in Halver, North Rhine-Westphalia, Germany. |
| 2009 | Renaming of Reitz GmbH & Co. KG to become SEISSENSCHMIDT Heat Treatment GmbH + Co. KG. Dr. Ekkehard Körner is appointed to the board at SEISSENSCHMIDT AG. HM 35 is added to the existing machinery. |
| 2010 | The machining hall of SEISSENSCHMIDT Components Processing GmbH + Co. KG undergoes expansion. New production line for SEISSENSCHMIDT Precision Components Kft. in Hungary provides a new spectrum of parts. |
| 2011 | Purchase of a new office building to expand the area of administration.. |
