Långhjelm demonstrated good leadership and organisational skills, and was recruited to leading position in shipbuilding and engineering company Wärtsilä in 1951.

His father Carl Långhjelm worked as chief inspector in a life insurance company; his mother was Alma née Holm.

Långhjelm wanted to further deepen his knowledge in electrical engineering and spent years 1928–1929 studying in UK after a scholarship.

Following the 1930s recession, the Finnish pulp and paper industry companies had started massive investments on machinery which led to growing orders of electrical components.

Långhjelm developed the factory in challenging circumstances in continuous lack of materials, labour, facilities and cash.

[1] Långhjelm's achievements were also noted by Wilhelm Wahlforss, general manager of the shipbuilding and engineering company Wärtsilä.

[1] Långhjelm took part in trade negotiations with Soviet Union; Wärtsilä got increasingly demanding ship orders from the eastern neighbour.

He had a strong role in 1956 introduced act, which strengthened the financial position of Finnish shipbuilders in international market by tax reliefs and improved credit terms; the law became known as Lex Långhjelm.