Kiernan first performed comedy in 1990 at the Comedy Club in the basement of the Blackfriars pub in Glasgow. He took up performing full time in 1993. A run of successful solo jobs led to his being offered a slot in the Edinburgh Comedy Festival in 1994, in a show called The Best Of Scottish Comedy, alongside John Paul Leach and Alan Taylor. Leach and Kiernan teamed up as a double act during this festival, and had shows at the next two festivals, After Eight Mince and The Full Bhoona, both at the Gilded Balloon.

Kiernan has had several bit-part roles in films. In 1996 he starred alongside Robert Carlyle in Carla’s Song and in 2002 he played the role of Black Joke Chief in the Martin Scorsese film Gangs of New York.

In 1999 and 2000 Kiernan and Hemphill also scripted seven episodes for the children’s TV series Hububb, and guest-starred in one of them, “Casual-Tea”.

In 2007 and 2008 Kiernan starred in Dear Green Place, a BBC One Scotland sitcom about park wardens. The show was co-written by Paul Riley and Rab Christie.

In January 2009 Kiernan starred in No Holds Bard, a one-off comedy special shown on BBC Scotland on Burns Night as part of a line-up of special programmes to mark the 250th birthday of Robert Burns.

Kiernan played a caravan park boss in the comedy Happy Hollidays. A pilot episode was shown on BBC 1 in early 2009 and a series was broadcast later in the year.

In October 2011 Kiernan played Gordon Brown in The Hunt for Tony Blair, a one-off episode of The Comic Strip Presents…

In 2011 and 2013 Kiernan played George McVie in The Field of Blood. In 2016 he played Felix in Journey Bound.

Kiernan lends his voice to the character of Banjo Barry in the animated film Sir Billi. The film was released in 2012.

In January 2014 Ford’s 12-year-old son Sonny was found dead in the family home. The stage show Still Game Live was dedicated to Sonny later that year.