[3] On 10 December 1645, he was created Baron Stuart of Newbury, Berkshire, and Earl of Lichfield, titles conferred on him "to perpetuate the titles which were intended to have been conferred on his uncle" Lord Bernard Stewart, youngest son of the Duke of Lennox, who had been killed in the Battle of Rowton Heath in the English Civil War in September of that year.

[5] He returned to England with King Charles II in 1660, on the Restoration of the Monarchy and sat in the Convention Parliament, showing great animosity towards the supporters of the Commonwealth.

On the death of his uncle, Ludovic Stuart, he succeeded him as 12th Seigneur D'Aubigny, for which title he did homage by proxy to King Louis XIV of France on 11 May 1670.

Firstly, after June 1659, to Elizabeth Rogers, and after her death, secondly, on 31 March 1662, to Margaret Banaster, widow of William Lewis, who died in 1666.

As he died without issue, his titles became extinct, with the exception of that of Baron Clifton, which passed with most of his property to his sister Katherine, Lady O'Brien.