For three years he was the only ordinary professor of mathematics at Heidelberg but from 1952 the department rapidly expanded. Seifert retired in 1975 and enjoyed gardening and entertaining his former colleagues and students.
Para sa tatlong taon na siya lamang ang karaniwang propesor ng matematika at Heidelberg ngunit mula sa 1952 ng departamento ng mabilis na lumago. Seifert nagretiro 1975 at masaya paghahardin at kinagigiliwan ng kanyang dating kasamahan at mga mag-aaral.