[4] In 1625 he inherited from his grandfather the manors of Great Tew and Burford in Oxfordshire, and, about the age of 21, married Lettice, daughter of Sir Richard Moryson, of Tooley Park in Leicestershire.

Following a quarrel with his father, whom he failed to propitiate by offering to hand over to him his estate, he left England to take service in the Dutch army, but soon returned.

His mother had embraced Roman Catholicism, to which it was now sought to attract Falkland himself, but his studies and reflections led him, under the influence of William Chillingworth, to the interpretation of religious problems rather by reason than by tradition or authority.

At Great Tew he enjoyed a short but happy period of study, and he assembled a cultured circle, whom the near neighbourhood of the university and his own brilliant qualities attracted to his house.

He supported the prosecution of Thomas Wentworth, 1st Earl of Strafford, at the same time trying more than once to moderate the measures of the House of Commons in the interests of justice, and voted for the third reading of the attainder on 21 April 1641.

On the question of the church he urged, in the debate of 8 February 1641, that the interference of the clergy in secular matters, the encroachments in jurisdiction of the spiritual courts, and the imposition by authority of unnecessary ceremonies, should be prohibited.

On the other hand, though he denied that episcopacy existed jure divino, he was opposed to its abolition; fearing the establishment of the Presbyterian system, which in Scotland had proved equally tyrannical.

On 1 January 1642, immediately before the attempted arrest of the five members, of which, however, Falkland was unaware, the King offered him the secretaryship of state, and Sir Edward Hyde (later Lord Clarendon) persuaded him to accept it.

In fact his sensitive nature shrank from contact with the practical politics of the day and prevented his rise to the place of a leader or a statesman.

Lord Clarendon has recorded his final relapse into despair: Sitting amongst his friends, often, after a deep silence and frequent sighs (he) would with a shrill and sad accent ingeminate the word "Peace, Peace," and would passionately profess that the very agony of the war, and the view of the calamities and desolation the kingdom did and must endure, took his sleep from him and would shortly break his heart.At Gloucester he had in vain exposed himself to risks.

On the morning of the First Battle of Newbury, on 20 September 1643, he declared to his friends, who would have dissuaded him from taking part in the fight, that "he was weary of the times and foresaw much misery to his own Country and did believe he should be out of it ere night."

He served during the engagement as a volunteer under Sir John Byron and, riding alone at a gap in a hedge commanded by the enemy's fire, was immediately killed.

This is a work of some importance in theological controversy, the general argument being that "to those who follow their reason in the interpretation of the Scriptures God will either give his grace for assistance to find the truth or his pardon if they miss it.