Christian was born in South West Wales and started composing whilst a pupil at Whitland Grammar School. Early works, such as Fantasia for Orchestra, Symphony for Wind and Gloria in Excelsis Deo (for brass band), gained performances and exposure on television and radio thanks to the encouragement of his music teachers at the time. His early promise was recognised with the awarding of the Grace Williams Memorial Prize twice at the Urdd Eisteddod (1991 and 1992), the Eisteddfod Scholarship (1991) and the S4C Schools Composition Price (1991). He was placed second in the adjudication for the music medal at the 1993 National Eisteddfod for his Wir Christenleut Toccata and won the SATB Choir composition competition at the 1994 National Eisteddfod. 

Christian continued his study of composition at the University of Surrey under Sebastian Forbes, graduating with first class honours. After this he wrote a series of works for children, most notably songs and incidental music for Charlie and the Chocolate Factory and Bring in the Holly (words by Charles Causley).

From October 2005 to September 2006 Christian studied at Cardiff University, obtaining his MMus with distinction. He was awarded a studentship to proceed to a PhD, which he began in October 2007, studying with Anthony Powers, Arlene Sierra and Judith Weir.

Subsequent performances include Mwg with Cardiff University Contemporary Music Group; a workshop performance of Movements for Orchestra with the BBC National Orchestra of Wales; Djemma el Fna with BBC National Orchestra of Wales brass and friends; Herr ich habe missgehandelt and Chorale from Lyra Davidica, both for organ. Reviewing Djemma el Fna in the Guardian, Rian Evans wrote ‘As a trumpeter himself, performing in this premiere, Morris’s sympathy for his medium was manifest…[the] final accumulation realised a vivid climax.’ The orchestral version of Lyra Davidica was performed by the BBC National Orchestra of Wales and broadcast on BBC Radio. Christian’s fanfare Variation XVI, was performed at the Arcomis International Brass Event in October 2013.

More recent composing has focused on choral repertoire, with new works commissioned by St. James’s Church, Sussex Gardens. These include an advent mass, Missa Veni, Veni Emmanuel (2015), Baptismal Sentences (2018), Three Tantum Ergos (2018) and the St. James Service (2019). His most recent work was a lockdown piece, Groove Study for Three Cellos, performed by US cellist Bryan Wilson (2021).

Christian has also written extensively on contemporary music. From 2011–19 he blogged regularly for compositiontoday.com, interviewing many leading figures, including Judith Weir, John Woolrich, Alasdair Nicolson and Philip Venables. His paper exploring composition procedures in Henri Dutilleux’s Symphony No. 2 was presented at the 2012 Sacher Perspectives Conference at Cardiff University and subsequently published in Tempo Music Journal (November 2013). He was awarded a stipend by the Paul Sacher Foundation to support his continued study of the composer in 2014.

In 2015 Christian returned to study at the Sacher Foundation, Basel, where he presented a paper on Henri Dutilleux on 18th May. This was followed by an article, published by the Sacher Foundation Mitteilungen in 2016. He has also co-authored a Spanish-language paper on Dutilleux, published by Mexican Music Journal Pauta in 2017.

Christian also has a vast experience writing and arranging music for amateur musicians. This work, which runs into thousands of pieces, can be found at 8notes.com, hooplasheetmusic.com and on his publishing page at SMP Press.