In 1545 he left Cologne to teach in a superior school, probably at Düsseldorf, after which he was rector at Hamm (1545–50), and head of the Pauline Gymnasium at Münster, which had formerly held a high reputation.
His first known work, written while he was in Cologne, was a poem in dactylic hexameters, Brevis descriptio belli Monasteriensis contra anabaptistica monstra gesti.
Kerssenbroch's position in Münster having become insupportable, he went to Paderborn, and while there, in spite of his oath, he published Catalogus episcoporum paderbonensium eorumque acta (Lemgo, 1578), availing himself of Person Gobelinus and others.
At Werl he prepared a vindication, Causarum captivitatis M. Hermanni a Kerssenbrock succinta narratio cum earundem vera et solida confutatione, which, however, was never printed.
To revenge himself upon his enemies, he resorted to a means which imperilled his life; he wrote a biting satire, "Noctua", in which he so exasperated his opponents that they sent a delegation to Werl to call him to account for perjury and breaking his oath, and his only safety lay in flight.