List of characters in Best Sister Ever and An Audience With Carstairs
| Name | Introduced in | Type | Description |
| Martin King | Best Sister Ever | Major | Protagonist. Former business man. Age 40. |
| Kate Castle | Best Sister Ever | Major | Martin’s sister, 16 years younger. Works for Keller & Fox talent agency. Age 24. Uses Castle as an alias. |
| Melody Warder | Best Sister Ever | Major | Talented artist, works in TV production. Age 26. |
| Diana Albinson | Best Sister Ever | Major | Actress. Owns theatre company. Age 51. |
| Kelly Newman | Best Sister Ever | Major | Young girl with medical issue. Martin’s biggest fan. Age 15. |
| Martin van de Casteele | Best Sister Ever | Major | Actual name of Martin King. King is his stage name. |
| Carstairs | Best Sister Ever | Major | Character performed by Martin. |
| Abishek | An Audience With Carstairs | Major | A confused elderly Indian gentlemen. See Colin Abhay. |
| Alice | Best Sister Ever | None | Bar girl at the theatre, takes over from Martin at light desk ad hoc. |
| Annabelle de Winter | Best Sister Ever | Major | Martin’s former secretary. Married, two children. |
| Ben | Best Sister Ever | Major | Martin’s landlord. |
| Boris Johnson | An Audience With Carstairs | Minor | Mayor of London. |
| Camilla | Best Sister Ever | None | Associate at Keller & Fox. Bad cop to Kate’s good cop, according to Kate. Unseen. |
| Caroline Keller | An Audience With Carstairs | Major | One of the owners of Keller & Fox. Age upwards of 40 and classified. |
| Chantal | And The Winner Is | None | Sister of Monique. |
| Colin Abhay | An Audience With Carstairs | Major | An actor who performs Abishek. |
| Derreck | Best Sister Ever | None | Director of the ‘Three’ commercial. |
| Dr. Sound | Best Sister Ever | None | Musical performer, associate of Kumquat. Not a doctor. |
| Edmund | Best Sister Ever | Minor | Sole musician of the theatre company. |
| Elisiah Carey | Best Sister Ever | None | A singer and guest on the Graham McAfee show. |
| Emma Lestrade | Best Sister Ever | Major | Actress. Age 25. |
| Eva | Best Sister Ever | None | Production assistant at commercial shoot. |
| Evert | Best Sister Ever | Minor | Martin’s former accountant. |
| Gillian | Best Sister Ever | None | Actor in the theatre company. |
| Graham McAfee | Best Sister Ever | Major | Talk show host, comedian. |
| Guy, a.k.a. Audio Guy | Best Sister Ever | Minor | Audio engineer at the theatre. |
| Hans de Winter | Best Sister Ever | None | Husband of Annabelle. Unseen. |
| Harold van de Casteele | Best Sister Ever | Minor | Father of Martin and Kate. Selectively deaf. |
| Harry | Best Sister Ever | Major | A massive rastafarian who befriends Martin. Speaks in Jamaican patois only. |
| John | Best Sister Ever | Minor | Actor in the theatre company. Plays The Detective, a.k.a. The Inspector. |
| Kees | And The Winner Is | Minor | Father of Monique. |
| Kim | Best Sister Ever | Minor | Budding actress, prostitute. |
| Kumquat | Best Sister Ever | Minor | Singer. |
| Leo | Best Sister Ever | None | Set manager at the theatre. |
| Linda Shearer, Dr. | Best Sister Ever | Minor | Medical doctor, assists when Simon has allergic reaction. |
| Lola | Best Sister Ever | Major | PR-girl of the theatre company. Extraordinarily shy. |
| Lucas | Best Sister Ever | Minor | Technician at the theatre. |
| Michiel Erp | And The Winner Is | Minor | Lawyer representing Martin in lawsuit against Tax Authority. |
| Mom | Best Sister Ever | Minor | Mother of Martin and Kate. |
| Monique | Best Sister Ever | Major | Martin’s ex wife. |
| Mrs. Bloothooft | And The Winner Is | None | Used to cook for Martin and Kate. Unseen. |
| Neil | Best Sister Ever | None | Production assistant at commercial shoot. |
| Nicholas Perry | An Audience With Carstairs | Minor | Director of the National Gallery. |
| Nigel | Best Sister Ever | Minor | Actor in the theatre company. Male lead. |
| Penny | Best Sister Ever | Minor | Dance instructor at Studio 68. |
| Peter Fox | An Audience With Carstairs | None | One of the owners of Keller & Fox. |
| Phil Smith | Best Sister Ever | Major | Actor, comedian. Age 44. |
| Phil, a.k.a. Audiophile | Best Sister Ever | None | Technician at the theatre. |
| Richard Maarsen | Best Sister Ever | None | Provides a loan to Martin after his company collapses. |
| Robert | And The Winner Is | None | Husband of Chantal. |
| Roger | Best Sister Ever | Minor | Dance instructor at Studio 68. |
| Rose | Best Sister Ever | Major | Retired actress. Now runs a B&B. |
| Sally | Best Sister Ever | Minor | Runs the bar at the theatre. |
| Samantha Wilder | An Audience With Carstairs | Major | A journalist with The Guardian. |
| Sebastian | An Audience With Carstairs | None | Son of Samantha Wilder. |
| Simon (audio engineer) | An Audience With Carstairs | None | Owner / operator of Black Magic audio studio. See also: Steve. |
| Simon Hastings | Best Sister Ever | Major | Warm-up comedian at Graham McAfee show, later host of An Audience With Carstairs. |
| Steve (audio engineer) | An Audience With Carstairs | None | Owner / operator of Black Magic audio studio. See also: Simon. |
| Susan | An Audience With Carstairs | Major | Aunty to Kelly. |
| Theo | Best Sister Ever | None | Musical performer, associate of Kumquat. Not a doctor. |
| Umar | An Audience With Carstairs | None | A Turkish photographer, sent by The Guardian for a portrait shoot. |
| Vera | Best Sister Ever | None | Actor in the theatre company. |
| Veronica | Best Sister Ever | None | Kate’s middle name is used for a fictitious sister, supposedly a flight attendant. |
| Welsh, duty officer | An Audience With Carstairs | Minor | Police officer who deals with Martin. |
| Willemijn | And The Winner Is | None | Mother of Monique. |
| Winston | And The Winner Is | Minor | IT-guy at Keller & Fox. |