Josephine's music has been performed by gambist Liam Byrne, violist Stephen Upshaw, violinists Eloisa-Fleur Thom and Fiona Monbet, explorensemble, The Hermes Experiment, the Van Kuijk Quartet, the Britten-Pears Contemporary Ensemble, Ensemble Miroirs Étendus, Outcry Ensemble, The Erebus Ensemble and the Maîtrise de Radio France among others, in venues such as the Auditorium de Radio France, the Bristol Old Vic, the Royal Albert Hall, Cafe Oto, National Portrait Gallery, St. John's Smith Square and LSO St Luke's in London. It has been broadcast on France Musique, BBC Radio 3 and BBC Radio 6 Music, and has appeared on television channels BBC Two and BBC Four.
In May 2014, her first opera On False Perspective, written with librettist Ben Osborn, was staged at the Britten Theatre as part of a collaborative project between the Royal College of Music and Tête à Tête Opera, and received positive reviews. In June of the same year she received a Composer Bursary from PRS/Bliss Trust to record her first orchestral piece Abend with Sinfonia d'Amici (cond. Harry Ogg), for whom the piece was written. The Classical Source described it as "a strong work matched with an equally strong performance", displaying "delicate textures" and a "kaleidoscopic orchestration". Her 40-part choral piece for the last night of the Bristol Proms 2015, if only, was described by Tom Morris as a "brilliantly ambitious piece, sparely and precisely scored, [which] seemed to paint the volume of air in the space with musical brush-strokes of precise detail".
Collaboration is central to Josephine's work. In 2016-17 she wrote music for the devised opera Les Constellations - une théorie, a collaboration with writer/director Antoine Thiollier and his theatre company l'Éventuel Hérisson Bleu with the Ensemble Miroirs Étendus, a project supported by Lille Opera. In 2015 she worked with FellSwoop Theatre on Ghost Opera, a devised music theatre piece for two actors, string quartet and tape which started life at the academy of the Festival d'Art Lyrique d'Aix-en-Provence and subsequently toured the UK. In July 2016 she was commissioned by the BBC and André de Ridder to write three arrangements for the David Bowie Prom at the Royal Albert Hall, collaborating with artists including Paul Buchanan (The Blue Nile) and Conor O'Brien (Villagers). Her interest in cinema has led her to make music for films, most recently the short film Emma, Change the Locks directed by Julia Hart and starring Olivia Williams ('Best Composer' at Underwire Festival 2015), as well as regularly assisting composers Dario Marianelli and Benjamin Wallfisch on major productions. She also enjoys working with songwriters and bands, and is an Artistic Director and resident composer of the London-based concert production company Listenpony, which puts on events mixing contemporary classical music with traditional classical music and popular styles.
Josephine is a graduate of Clare College, Cambridge, where she studied composition with Giles Swayne, and the Royal College of Music, where she was a Richard Carne scholar and studied with Kenneth Hesketh. She has participated in masterclasses led by composers such as Samuel Adler, Mark-Anthony Turnage, Colin Matthews, Oliver Knussen, Georg Friedrich Haas or Ivan Fedele. She was a 2015/16 Britten-Pears Young Artist.