Chadwick entered New England Conservatory as a "special student" in 1872, where he could study with the faculty without satisfying the rigorous entrance or degree requirements. However, he approached his studies more seriously and took advantage of what NEC offered. Chadwick studied organ with George E. Whiting (1840-1923), piano with Carlyle Petersilea (1844-1903), and theory with Stephen A. Emery (1841-1891), each of whom was well-respected in the Boston music scene.
In 1876, Chadwick accepted a faculty position within the music program at Olivet College and was a valued instructor as well as administrator. While at Olivet, Chadwick founded the Music Teachers National Association. The first evidence of his interest in composing appeared during this time, from a performance of his Canon in E-flat dated 6 November 1876.
Realizing that his musical career in the U.S. would be limited without further studies in Europe, Chadwick headed to Germany like many other composers of his generation. He studied in Leipzig at the Royal Conservatory of Music under Carl Reinecke (1824-1910) and Salomon Jadassohn (1830-1902). Chadwick's most significant compositions as a student there include two string quartets (no. 1 1877-8, no. 2 premiered 1879) and the concert overture Rip Van Winkle. They helped confirm his position as a promising young American composer among his German contemporaries, from whom he received favorable critiques.
After his two-year stay in Leipzig, Chadwick traveled around Europe with a group of artists who called themselves the "Duveneck Boys". They were led by the young and charismatic Frank Duveneck, who was well-known for his portrait works in the style of VelÃ¡zquez. The group was based in Munich, then major culture center second to Paris. Chadwick also stayed in France with the group, where he was taken with the French lifestyle and influenced by the emerging Impressionist movement.
Chadwick resumed his compositional studies with Josef Rheinberger (1839-1901) at the Hochschule fÃ¼r Musik in Munich. Rheinberger was known as a skilled musical craftsman who incorporated polyphony with creativity and clarity. Thus Chadwick benefited from Rheinberger's extensive knowledge of the classics, both instrumental and choral.
Chadwick returned to Boston in March 1880 and soon began establishing a career in the U.S. He opened a teaching studio and secured two performances of Rip Van Winkle. Chadwick also completed his First Symphony, which although not particularly inspired was a significant early contribution by an American composer. In addition to his compositional activities, Chadwick was also a performing organist and avid conductor. He served as the Music Director of the Springfield Festival from 1890 to 1899, and of the Worcester Festival from 1899 to 1901.
In 1897, Chadwick was appointed Director of New England Conservatory. Known in the Boston arts circle as talented, personable, and energetic, he was crucial in transforming NEC into a respectable school of music. Chadwick implemented features that resembled those of the German conservatories of his experience. He established a variety of performing ensembles, and students were required to take more music theory and history classes. He had some influence in the establishment of Phi Mu Alpha Sinfonia music fraternity, which was established at the conservatory in the fall of 1898. He also invited members of the Boston Symphony Orchestra as private teachers to the students, along with being an inspiring teacher himself. His students described him as "demanding, though fair-minded and witty".
Chadwick composed in almost every genre, including opera, chamber music, choral works, and songs, though he had a particular affinity for orchestral music.