Mathews has contributed to many sketch shows, including Harry Enfield and Chums, The All New Alexei Sayle Show and the Ted & Ralph segments of The Fast Show.

However, it was with Father Ted (three series, 1995–1998) that he and Graham Linehan made their biggest impression. It debuted on Channel 4.[1][2][3] The writing partnership had previously co-written the comedy Paris[4] (one series, 1994), also for Channel 4.