Calvert, George (d. 1632), 1st Baron Baltimore , politician, was born in Yorkshire, the son of Leonard Calvert of Danby Wiske, Yorkshire, and his wife, Alice, daughter of John Crossland of Crossland, Yorkshire. He perhaps had a younger brother. He studied at Trinity College, Oxford, from 1594 to 1597, and graduated BA in 1597 and MA in 1605. He entered Lincoln's Inn on 16 August 1598. He married Anne (1579–1621/2), daughter of George and Elizabeth Mynne of Hertingfordbury, Hertfordshire, on 22 November 1604; they had twelve children (six sons and six daughters, of whom three sons and one daughter predeceased their father). With his second wife, Joan (d. 1630), he had one son. From 1605 he acted as secretary to Robert Cecil, earl of Salisbury, was elected to parliament for Bossiney in Cornwall in 1609 through Salisbury's influence and was appointed one of the clerks of the English privy council in July 1610. He had been granted a reversion to the post of clerk of the crown for Connacht and Clare on 10 July 1606 (patent 3 September) and was named one of the overseers of the musters for Ireland on 27 December 1611.
On 27 August 1613 he was one of four commissioners named alongside Lord Deputy Chichester (qv) to investigate grievances brought to court by catholic representatives from Ireland, particularly with respect to the composition of the Irish parliament that had met earlier that year. The commissioners’ report (12 November 1613) found few cases of electoral malpractice, minimised other parliamentary complaints and generally vindicated Chichester's government.
Calvert was appointed one of the two English secretaries of state, and a privy councillor, in February 1619, and acted as a treasury lord from January to December 1620. He took a prominent role in the parliament of 1621, in which he sat for Yorkshire, and represented Oxford University in the parliament of 1624. As senior secretary, he appears to have held responsibility for day-to-day conduct of foreign affairs from 1620 to 1623, but his political influence was on the wane by 1623–4, as his pro-Spanish outlook became increasingly at odds with England's drift to war with Spain and more of the important diplomatic correspondence was being handled by his fellow secretary, Conway. By April 1624 he seems to have been considering selling his post, and he resigned as secretary on 12 February 1625.
He retained royal favour: having been knighted on 29 September 1617, he was created Baron Baltimore in the Irish peerage on 16 February 1625. At the same time he gained confirmation of the lands in Co. Longford granted to him in 1622. He had also been granted lands at Danby Wiske, Yorkshire, and had purchased further property at Kiplin in that county. Following the accession of Charles I (27 March 1625) he resigned from the privy council, citing his inability to renew subscription to the oath of supremacy, given his now open profession of Roman catholicism. Having sold his Longford lands he had purchased property at Clohamon, Co. Wexford, where he resided for a time with his family, and to which he drew English tenants, the majority of them catholic by 1638.
Baltimore's long-standing interest in North American colonisation included the award of a patent in 1623 for territory in Newfoundland, to which he travelled in 1627 and 1628–9; by then convinced of the area's unsuitability for the type of settlement he had already launched, he returned to London and sought from Charles I a proprietary grant of lands further south. Plans for a grant in the Chesapeake region, the future Maryland, were well advanced at his death, which occurred in London on 15 April 1632, and a grant of Maryland was duly made to his heir, Cecil Calvert, 2nd Baron Baltimore, on 20 June 1632. The city of Baltimore, Maryland, was named for the family. A portrait of George Calvert by Daniel Mytens exists from 1627.