Henry Arnold was born in Hamburg on May 10, 1961. He grew up in Munich, where he attended the Munich Academy of Music as a guest student of piano while still in high school. After graduating from high school in 1980, he attended the acting school Neue Münchner Schauspielschule and studied German language and literature, musicology and history for six semesters in Munich and Berlin; in 1989/90 he attended the Berlin Hochschule der Künste (now: Universität der Künste) to study conducting. In addition to these artistic trainings, Arnold also completed a degree in economics. 

In the mid-1980s, Arnold began working as an actor. He appeared on stage at Berlin's Schillertheater and Zurich's Schauspielhaus, among others. In 1987, he was hired by Edgar Reitz to play the lead role in his 13-part epic "Die zweite Heimat - Chronik einer Jugend" ("Heimat 2: A Chronicle of a Generation"). Filming lasted almost four years, and the premiere took place at the 1992 Venice Film Festival. Arnold's portrayal of the music student and later conductor and composer Hermann Simon brought him much critical praise and international recognition. At the Grimme Prize, Arnold, Reitz and the actresses Salome Kammer, Hannelore Hoger and Anna Thalbach won in the series/multi-part category. 

In 1993/94, Henry Arnold appeared on stage at the Staatliche Bühnen Berlin in Shakespeare's "A Midsummer Night's Dream" (directed by Hans Neuenfels); at the Schauspielhaus Zurich, he had a leading role in "Tanz auf dem Vulkan" in 1998. Until 2001 he took part in several productions of the Schwäbisch-Hall Festival. In 1996 Arnold also began to work as a director, initially alongside Hans Neuenfels as an assistant director, later as the director in charge. 

In addition, he appeared in several television productions. For his co-starring role in Markus Imboden's television drama "Ausgerechnet Zoé" (1994), he was again awarded the Grimme Prize (together with Imboden, Rainer Klausmann and Nicolette Krebitz). In Italy, he was part of the main ensemble of Marco Bellocchio's "Il Sogno della Farfalla" ("The Dream of the Butterfly ", 1994.) He also played supporting parts in the drama "Mein zweites Leben" (1997) and the comedy "Drei Gauner, ein Baby und die Liebe" (1998), among others. Arnold had a continuous leading role in the series "Mama und ich" (2001-2002), as a casual Porsche driver and good friend of the main character.  

In 2002/2003, Arnold reprised the leading role of Hermann Simon for Edgar Reitz's six-part series "Heimat 3 - Chronik einer Zeitenwende" ("Heimat 3: A Chronicle of Endings and Beginnings"). The premiere took place in September 2004, again at the Venice Film Festival. In the years that followed, he had mainly guest roles in television series, among them "Alphateam - die Lebensretter im OP" (2005), "In aller Freundschaft (2007) and "SOKO Leipzig" (2009). 

From 2000 onwards, Henry Arnold also regularly directed stage plays, e.g. "Zar und Zimmermann" at the Staatstheater Darmstadt (2002), "Hoffmanns Erzählungen" at the Stettin Opera (2005) and "Die Geschichte vom Soldaten" at the Stadttheater Gießen (2008), to name just a few. In summer 2010 he took over the dramaturgy at the Bayreuth Festival as well as a direction of a new production of "Lohengrin". At the Vorarlberger Landestheater in Bregenz, he was responsible for directing "Die lustige Witwe" (2010), "Fidelio" (2019) and "La Clemenza di Tito" (2020).  

As an actor, Arnold repeatedly appeared on stage at Hamburg's Ernst Deutsch Theater between 2009 and 2018; under the direction of Paulus Manker, he appeared in several productions at Theater Wiener Neustadt in 2019/20. On the big screen, he had supporting roles in Nicolas Wackerbarth's "Halbschatten" ("Everyday Objects", DE/FR 2013), Philip Gröning's "Mein Bruder heißt Robert und ist ein Idiot" ("My Brother's Name Is Robert and He Is An Idiot", DE/FR/CH 2018) and the British production "Zuriel's Diary" (2018). On television, he appeared in the comedy "Urlaub mit Mama" (2018) and in the series "Rote Rosen" (2017) and "SOKO Wismar" (2022). In September 2022, Henry Arnold staged the musical "I do! I do!" at the Plauen-Zwickau Theater.