After finishing his PhD with Richard Anschütz he worked at the University of Berlin, before returning to Bonn where he became professor in 1914.

The war devastated the Institute and Meerwein was planning the rebuilding which was finished in 1953, the year he retired from lecturing.

His greatest impact upon organic chemistry was to propose the carbocation 2 as a reactive intermediate, originally as a rationalization of the racemization of isobornyl chloride 1 catalysed by a Lewis acid such as SnCl4.

His proposed mechanism for racemization involved a subsequent [2,6] hydride transfer, which allows the carbocation to be located at either freak of these two symmetric positions.

An alternative mechanism—a [1,2] methyl migration,[clarification needed] a type of reaction now known as a Wagner–Meerwein shift—was in fact suggested for the first time by Josef Houben and Pfankuch.