Marriage and issue
In 1585, Charles married Catherine Michaela of Spain, daughter of Philip II of Spain and Elizabeth of Valois. They had:
Filippo Emanuele, Prince of Piedmont (1586–1604);
Victor Amadeus I, Duke of Savoy (1587–1637), married Christine Marie of France, and had issue;
Emanuel Filibert (1588–1624), Spanish Viceroy of Sicily (1622–24);
Margherita (1589–1655), married Francesco IV Gonzaga of Mantua;
Isabella (1591–1626), married Alfonso III d'Este, Hereditary Prince of Modena;
Maurice, a cardinal (1593–1657);
Maria Apollonia, a nun in Rome (9 February 1594 – 13 July 1656);
Francesca Caterina, a nun in Biella (6 October 1595 – 26 September 1640);
Thomas Francis, Prince of Carignano (1596–1656) married Marie de Bourbon, Countess of Soissons and had issue;
Giovanna (born 6 October 1597) died at birth.
In Riva di Chieri on 28 November 1629, he secretly married his long-time and official mistress, Marguerite de Rossillon, Marchesa di Riva di Chieri (bap. 24 December 1599 – 10 November 1640), with whom he had four children, legitimised after the wedding but without succession rights:
Maurizio (died 1645), Marchese di Poirino, Cavalry colonel.
Margherita (died 1659), Signora of Dronero, Roccabruna e San Giuliano, married Filippo Francesco d’Este, Marchese di San Martino in Rio (ancestors of Maria Teresa Cybo-Malaspina).
Gabriele (died 1695), Marchese di Riva, Cavalry lieutenant general.
Antonio (died 1688), Abbot of San Michele della Chiusa (1642), of Santa Maria d’Aulps (1645), of Altacomba (1653), of Fruttuaria di San Benigno (1660) and Casanuova (1687), Lieutenant General of the County of Nice (1672).
In addition, he had several illegitimate children:
— With Luisa de Duyn Maréchal, daughter of Jean-Marie de Duyn, called Maréchal, baron of Val d'Isère:
Emanuele (1600–1652), Marchese di Andorno and Valle 1621, Governor of Asti and Biella. Knight of the Order of St Maurice and Lazarus.
— With Virginia Pallavicino:
Carlo Umberto (1601–1663), Marchese di Mulazzano con Gonzole, married Claudia Ferrero-Fieschi, daughter of Francesco Filiberto Ferrrero' Fieschi, prince 1598 of Masserano and Crevacuore.
Silvio (died 1645), Abbot Commander of Santa Maria d’Entremont (1631), of San Lorenzo fuori le mura d’Ivrea (1642), Governor of Ivrea (1641).
Vitichindo (d. 1668 or 1674), priest.
— With Argentina Provana, daughter of Giovanni Francesco Provana, count of Bussoleno and Collegno, and Anna Maria Grimaldi:
Felice (1604–1643), Marchese di Baldissero d’Alba, Signore of Farigliano, Sessanta, Serravalle e Sommariva del Bosco (1629), Lieutenant of the County of Nice 1625/1632.
— With Anna Felizità Cusani:
Ludovico Cusani (died 1684), Knight of the Order of Saint Maurice and Lazarus.
— With unknown mistress:
Anna Caterina Meraviglia (died 1660).