Catherine of Braganza became queen consort when she married Charles II at Portsmouth in May 1662, in private Catholic and public Anglican ceremonies. The treaty joined English support for Portugal to a dowry that included Tangier, Bombay and commercial privileges. Delays in paying the promised money complicated her position, while her Catholic faith distinguished her household from England's established church.

Catherine maintained her own chapel and Portuguese connections, corresponding with Rome and protecting Catholic worship within her household. Her position at court was repeatedly strained by Charles's mistresses, particularly Barbara Palmer, whose appointment to her household she initially resisted. Several pregnancies ended in miscarriage, leaving no surviving child. During the Popish Plot panic of 1678, accusations that she participated in a scheme to poison the king were unsupported, and Charles refused to abandon her. She continued the ceremonial and household duties of a queen despite these pressures.

After Charles died in 1685, Catherine remained in England through James II's reign and the accession of William and Mary. She negotiated her return to Portugal in 1692 and eventually established herself at the palace of Bemposta near Lisbon. Her brother Peter II entrusted her with the regency during his illnesses in 1701 and 1704–1705. She was still acting as regent when she died in December 1705, having moved from consort's household to direct royal government.