Maria Gonzaga hatte sich in ihrer Jugend in den jüngeren Bruder des französischen Königs Ludwig XIII., Gaston (1608-1660), den Herzog von Orléans, verliebt, aber diese gegenseitige Liebe führte nicht zu einer Eheschließung, da Gastons Mutter, die französische Königin Maria de' Medici dagegen war: "Monsieur [Gaston], the king's brother, had been in love with her when he was presumptive heir to the crown. The queen his mother, Marie de' Medici, who had other designs for him, feared his passion, and sent the Princesse Marie [Gonzaga] to Vincennes, where she was for some time innocent victim of a laudable affection." (in: Memoirs of Madame de Motteville, Volume 1, id., p. 133).
Letztendlich wurde Maria am 10. März 1646 die Gattin des polnischen Königs Wladyslaw IV. (1595-1648) und nach seinem Tod am 30. Mai 1649 die Gattin von seinem Halbbruder Johann II. Kasimir (1609-1672), dem neuen König von Polen. Aus beiden Ehen gingen keine Kinder hervor.
Madame de Motteville, die Hofdame der französischen Königin Anna von Spanien/Österreich, berichtet über die polnische Gesandschaft, die im Namen ihres Königs Wladyslaw IV. im Jahr 1645 um die Hand von Maria Gonzaga bat: "The Polish ambassadors were received at Fontainebleau in the great salon of the queen [Anna von Spanien/Österreich], whose apartments are very beautiful. When they entered, the Princesse Marie [Gonzaga] was in the circle. She rose, so as not be present at their harangue, and retired to a corner of the room to see them from a distance. She made use of me to screen herself from their sight, and by putting me before her prevented the men who were to be her subjects from perceiving her. After the ceremony, which only lasted the length of a compliment, these persons, who were all dressed in the French fashion and did not seem like foreigners, asked where she was. Some among them, who had already been in France, knew her, and pointed her out to the ambassadors. We saw them turn towards her to salute her, and as I did not hide her much, in spite of her efforts, one of them, as he withdrew, made her a profound bow and all the others in his suite did likewise. At the audience which he had with her the next day he treated her as Majesty and with the same respect as if she had already been his queen. ... During the winter we beheld the second Polish embassy ... The Palatine of Posnania and the Bishop of Warmy were those whom the King of Poland selected to come and marry Princesse Marie and bring her to him. They chose to appear dressed in the fashion of their country, the better to show their magnificence and the splendour of their stuffs. ... [Die Braut Maria Gonzaga sah folgendermaßen aus:] She had a fine figure, and was then of a reasonable plumpness. She was thirty-three years old. Her eyes were black and handsome, hair of the same colour, complexion and teeth beautiful, and the other features of her face neither handsome nor ugly; but altogether she had beauty, with the grand air in her person that befits a queen. She seemed to deserve all she had expected to have in marrying the Duc d'Orléans [Gaston], and all she was really to have in marrying a king. Her wedding dress was a body and petticoat of cloth of silver with silver embroideries. Above this she had intended to wear her Polish royal mantle, which is white, strewn with great flashes of gold; but as the marriage was performed without ceremony the queen [Anna von Spanien/Österreich] was of opinion that she ought not to wear it. ... She was decked with the pearls and diamonds of the crown, which the queen had put together with her own hands. This adornment accompanied a closed crown made of large diamonds and very large pearls of great price. When she was ready to put the crown on her head, she doubted if she ought to do so before the ceremony, and she ordered me to go to the queen and ask her opinion; the queen did me the honour to tell me that as yet she had no right to wear it. When she was dressed she wished to show herself to the queen, who was in her own apartment, and she crossed the terrace which joins the two buildings, with two of her friends, my sister and myself. The Poles, who were in the courtyard below awaiting the hour of the mass, seeing her, sent up shouts of joy and gave her many benedictions. .. The queen, who was wearing her great pearls and her mourning mantle, then led the princess to the chapel through the great gallery. There was no one present but the king [Ludwig XIV.], the queen, the queen that was to be, the little Monsieur [Philippe I., der kleine Bruder von Ludwig XIV.] and the Duc d'Orléans [Gaston]. The princess knelt upon the foot-cloth laid in the centre of the chapel, the king on her right side, the queen on her left. Monsieur the king's brother, and the Duc d'Orléans, the king's uncle, were behind on their knees upon the foot-cloth; consequently the latter was for this day her inferior. This moment, when she saw herself raised above that faithless prince [Gaston], above even the queen whose subject she had been before her father became sovereign, was no doubt most agreeable and glorious to her. The Bishop of Warmy celebrated the mass and the marriage of his king and queen, whom the Palatine married in the name of his master. After the mass was said they placed the crown upon her head. ... Besides the Poles, there was no one in the chapel but the royal personages and those of the blood royal whom I have just named, except the Maréchale d'Estrées, Madame de Montausier, and Madame de Choisy. The last three were the intimate friends of the Queen of Poland, and she had entreated the queen to allow them to be present. Madame de Bregi, my sister, and I were also present." (in: Memoirs of Madame de Motteville, Volume 1, id., pp. 134-140).
Und wie war der Empfang von Maria Gonzaga in Polen im Jahr 1646: "... her joy was evaporated by the presence of the king [Wladyslaw IV.] she had come so far to seek. In Warsaw she was received with little acclamation, for the king was old, oppressed with gout and fat, and so ill and gloomy that he would allow no ceremonies on her arrival. He did not think her as handsome as her portraits, and showed no esteem for her person. I heard from the Maréchale de Guébriant, who accompanied her by order of the queen, that this old husband received her in church seated on a chair from which he did not rise, or even pretend to do so. When she came beside him she knelt and kissed his hand. He received her salute without the slightest sign of gentleness or benignity. He looked at her gravely and let her kiss his hand without saying a word. Then he turned towards Bregi, the ambassador, who stood beside him, and said aloud: 'Is that the great beauty about which you told me wonders?'" (in: Memoirs of Madame de Motteville, Volume 1, id., p. 141).