His paternal grandparents were Frederick Francis I, Grand Duke of Mecklenburg-Schwerin, and Princess Louise of Saxe-Gotha-Altenburg.{{cite book |last= Haydn|first= Joseph| title =History of the Wars of the French Revolution | publisher =Bangs| year =1855| pages =555}} His maternal grandparents were Duchess Sophie Dorothea of Württemberg and Tsar Paul I of Russia; he was the only surviving grandchild born during the Tsar's lifetime.

He was educated at Geneva, Jena and Rostock. Upon the death of his father, the Hereditary Grand Duke, in 1819, Paul Friedrich became heir-apparent to the throne of Mecklenburg-Schwerin.

Career

On 1 February 1837 he succeeded his grandfather, Friedrich Franz I. His reign saw improvements in the infrastructure and judicial system of the Grand Duchy, as well as a change in the government's seat of residence from Ludwigslust to Schwerin. Nonetheless, Paul Friedrich was largely interested only in military matters and spent most of his time drilling his troops. As Paul Friedrich reached his middle age, he adopted a more reclusive lifestyle, preferring only the company of his mistress.

Personal life

File:Alexandrine von Mecklenburg and her children, by Friedrich Wilhelm von Schadow.jpg and children, Friedrich Franz II and Luise, by Friedrich Wilhelm Schadow, {{circa|1825}}]]

On 25 May 1822 at Berlin, Paul Friedrich married Princess Alexandrine of Prussia (1803–1892), the seventh child and fourth daughter of King Frederick William III of Prussia and Duchess Louise of Mecklenburg-Strelitz. Together, they had two sons and one daughter:

Friedrich Franz II of Mecklenburg-Schwerin (1823–1883), who married Princess Augusta Reuss of Köstritz, a daughter of Prince Heinrich LXIII Reuss of Köstritz, and Countess Eleonore of Stolberg-Wernigerode, in 1849. After her death in 1862, he married Princess Anna of Hesse and by Rhine, the only daughter of Prince Karl of Hesse and by Rhine, and Princess Elisabeth of Prussia, in 1864. She died in 1865 and he married, thirdly, to Princess Marie of Schwarzburg-Rudolstadt, the daughter of Prince Adolph of Schwarzburg-Rudolstadt and Princess Mathilde of Schönburg-Waldenburg, in 1868.{{in lang|fr}} Hélène de Mecklembourg-Schwerin; Madame la duchesse d'Orléans; Nouvelle édition. Paris: Michel Lévy, 1859. DC 269 .O7 M34 1859.
Duchess Luise of Mecklenburg-Schwerin (1824–1859), who married Hugo, 2nd Prince of Windisch-Graetz, second son of Weriand, 1st Prince of Windisch-Graetz.{{cite book |last1=Dietrich |first1=Andrea |last2=Müller |first2=Winfried |last3=Schattkowsky |first3=Martina |title=Zwischen Tradition und Modernität: König Johann von Sachsen 1801-1873 |date=2004 |publisher=Leipziger Universitätsverlag |isbn=978-3-936522-86-0 |page=364 |url=https://www.google.com/books/edition/Zwischen_Tradition_und_Modernit%C3%A4t/hDDXRMQY_f4C?hl=en&gbpv=1&pg=PA364 |access-date=17 March 2025 |language=de}}{{cite book |last= Huberty |first= Michel |author2=Alain Giraud |author3=F. B. Magdelaine |title= L'Allemagne Dynastique, Tome VI : Bade-Mecklembourg |year= 1945 |isbn= 978-2-901138-06-8 |pages=233, 239 }} After her death in 1859, he married Princess Matilda Radziwill, the daughter of Prince Friedrich Wilhelm Radziwill, 14th Duke of Nieśwież (eldest son of Prince Antoni Radziwiłł), and Princess Mathilde Christina of Clary-Aldringen, in 1867.{{cite book |last1=Fries |first1=Jana Esther |last2=Gutsmiedl-Schümann |first2=Doris |title=Ausgräberinnen, Forscherinnen, Pionierinnen: Ausgewählte Porträts früher Archäologinnen im Kontext ihrer Zeit |date=2013 |publisher=Waxmann Verlag |isbn=978-3-8309-7872-5 |page=44 |url=https://www.google.com/books/edition/Ausgr%C3%A4berinnen_Forscherinnen_Pionierinn/mPje7098z0gC?hl=en&gbpv=1&pg=PA44 |access-date=17 March 2025 |language=de}}
Duke Wilhelm of Mecklenburg-Schwerin (1827–1879), who married Princess Alexandrine of Prussia, daughter of Prince Albert of Prussia and Princess Marianne of the Netherlands.{{Citation | title = Romances of a Royal House | newspaper = The Washington Post | date = 20 April 1906 | accessdate = }}{{cite book|first=Christopher|last=Hibbert|title=Edward VII: The Last Victorian King|publisher=Palgrave Macmillan|location=New York|year=2007|page=41}}

Paul Friedrich also had issue with his mistress, Countess Catharina von Hauke, daughter of Johann Mauritz Hauke and sister of Princess Julia of Battenberg, including:{{cite book |title=Bayerischer Veteranen-Kalender: für .... 1890 |date=1890 |publisher=Reichel |page=45 |url=https://www.google.com/books/edition/Bayerischer_Veteranen_Kalender/jeiIR7IDM7oC?hl=en&gbpv=1&pg=RA2-PA45 |access-date=17 March 2025 |language=de}}