Captain Paul Collis-Smith joined the Army in September 1990 and attended one year's training at the Army Junior School of Music. He became Junior Sergeant and won the 'Best Brass Player' and 'Best Overall Musician' prizes.

In 1991 to 1993 he attended the pupil's course at the Royal Military School of Music and won a parchment for 'exceptional proficiency on the cornet'.

In 1994 he was posted to the newly formed Clive Band of the Prince of Wales's Division and became principal cornet. During this time he gained a Licentiate teacher's diploma (trumpet) from the Trinity College of Music.

In 2001 he was promoted to Sergeant and selected for the Bandmasters' course at the Royal Military School of Music Kneller Hall.  On completion he gained an honours degree in music and won a prize for the 'British student gaining highest marks in the MoD examinations'.

During the Bandmasters' course he ran the Kneller Hall Fanfare Team for two years, performing for Her Majesty The Queen on several occasions and appearing on the Royal Variety Performance.

He was appointed Bandmaster in 2004 and posted to the Band of the Royal Gibraltar Regiment. In addition to public duties in Gibraltar, the Band took part in public duties in London and training exercises in Morocco and the Gambia.

In 2006, he returned to the Royal Military School of Music for a short time as Museum Warrant Officer, tasked with a curator role within the School Museum. 

In January 2007, he was posted to the Band of The Life Guards and after completion of riding school in May 2007.

In September 2011 he was commissioned and became the Director of Music for the Band of the Royal Regiment of Scotland.