Lawson was in command of ships in the parliament's service during and after the English Civil War, 1642-6, 1651-3, 1654-6. He was dismissed from the public service, apparently on political grounds in 1656. An anabaptist and republican, he was implicated in the conspiracy of the Fifth Monarchists and arrested in 1657. He was appointed commander-in-chief of the fleet in 1659 and co-operated with General George Monck in the restoration of the monarchy in 1660. A grateful King Charles II of England knighted him in 1660. Commissioned as the vice-admiral of the red squadron for the Second Anglo-Dutch War in 1665, he died of a wound received at the battle of Lowestoft.