In his extra-literary life, Carlell was a courtier and royal functionary; he held the offices of Gentleman of the Bows to King Charles I, and Groom to the King and Queen's Privy Chamber. He was also Keeper of the Great Forest at Richmond Park. In the latter post, he assisted the King in his frequent hunts, and throughout the 1630s he lived in the lodge of the deer park at Richmond. In this same period he accomplished most of his dramatic authorship — and his plays are notable for their forest scenes.
Interestingly, he maintained his post at Richmond Park throughout the English Civil War, down to 1649. In this period he may have acted as a sort of undercover agent for the Royalist cause; he is thought to have sheltered Lucy Hay, Countess of Carlisle during this time. During the English Interregnum he is thought to have remained the Keeper both of Richmond Park and St. James's Park.
His extant plays (followed by date of publication) are: The Deserving Favourite (1629), Arviragus and Philicia, parts 1 and 2 (1639), The Passionate Lovers, Parts 1 and 2 (1655), The Fool Would be a Favorite, or The Discreet Lover (1657), Osmond the Great Turk, or The Noble Servant (also 1657), and Heraclius, Emperor of the East (1664), the last a translation of the 1647 play by Pierre Corneille.
Some critics have judged his plays to be significant in the evolution of serious drama in the 17th century, from the tragedy and tragicomedy of John Fletcher and his collaborators to the "heroic drama" of the Restoration era. In this view, Carlell is "one of the chief intermediaries between Beaumont and Fletcher, and Dryden and Settle.
Carlell was buried on August 21, 1675, in the Church of St.-Martin-in-the-Fields in Petersham in Middlesex.