For a short time he ran the family law department of a small firm of city solicitors and then became an advertising copywriter for Ogilvy and Mather.
Whilst working as creative director for a major London advertising agency, he began writing his first television series.
Mendelson's most recent television situation comedy series in the UK is My Hero which ran for six seasons on BBC One from February 2000 to September 2006.
Based on his own experiences with testicular cancer he wrote the acclaimed ITV play Losing It, starring Martin Clunes, for which he was nominated Televisual Awards Best Writer 2007.
Paul Mendelson created the original idea and is creative consultant on the DreamWorks Animation/Fox forthcoming series 'Neighbors from Hell'.