- Daniel Radcliffe ......................... Harry Potter
- Rupert Grint .............................. Ron Weasley
- Emma Watson ........................... Hermione Granger
Hogwarts
- Michael Gambon .......................... Albus Dumbledore
- Jim Broadbent ............................. Horace Slughorn
- Alan Rickman .............................. Severus Snape
- Robbie Coltrane ............................ Rubeus Hagrid
- Maggie Smith ............................... Minerva McGonagall
- Warwick Davis ............................. Filius Flitwick
- David Bradley .............................. Argus Filch
- Bonnie Wright .............................. Ginny Weasley
- Matthew Lewis .............................. Neville Longbottom
- Evanna Lynch ............................... Luna Lovegood
- Tom Felton .................................... Draco Malfoy
- Jessie Cave .................................... Lavender Brown
- Georgina Leonidas .......................... Katie Bell
- Isabella Laughland ......................... Leanne
- Anna Shaffer ................................. Romilda Vane
- Scarlett Byrne ................................ Pansy Parkinson
- Alfie Enoch ..................................... Dean Thomas
- Devon Murray ................................ Seamus Finnigan
- Shefali Chowdhury ......................... Parvati Patil
- Afshan Azad ................................... Padma Patil
- Jamie Waylett ................................ Vincent Crabbe
- Josh Herdman ................................ Gregory Goyle
- William Melling .............................. Nigel
- Katie Leung .................................... Cho Chang
- Greta Bellamacina .......................... Pansy Parkinson’s friend
- Melanie Slade ................................. Quidditch tryout spectator
- Dean Garmhan ............................... Slytherin Student
- Katy Newman Wood ....................... Hogwarts Student
Slug Club (and related)
- Freddie Stroma .............................. Cormac McClaggen
- Louis Cordice ................................. Blaise Zabini
- Robert Knox ................................... Marcus Belby
- Amber Evans ................................. Flora Carrow
- Ruby Evans ................................... Hestia Carrow
- Charlie Bennison ............................ Sanguini the vampire
- Tom Moorcroft ................................ Regulus Black (photograph in Slughorn's house or office)
- Alec Hopkins ................................... Young Severus Snape (photograph)
- Tony Coborn ................................... Young Lucius Malfoy (photograph in Slughorn’s house or office)
- River George ................................... Laurasia
- Nina Voelker .................................... Wendy Slinkhard
- Elliot Francis .................................... 6th Year/Slug Club Member
- Guy Mannerings ............................... Slug Club Member in Tom Riddle’s time
- Daniel Barnett .................................. Hogwarts Graduate attending Slughorn’s Party
- Sam Gaukroger ................................. Hogwarts Student
- Dean Mitchell .................................... Slug Club Wizard
Order of the Phoenix Members
- Mark Williams .................................... Arthur Weasley
- Julie Walters ...................................... Molly Weasley
- David Thewlis ..................................... Remus Lupin
- Natalia Tena ....................................... Nymphadora Tonks
- James Phelps ...................................... Fred Weasley
- Oliver Phelps ...................................... George Weasley
Death Eaters (and related)
- Helena Bonham Carter ......................... Bellatrix Lestrange
- Helen McCrory ..................................... Narcissa Malfoy
- Jason Isaacs ......................................... Lucius Malfoy (cameo in a newspaper and a portrait)
- Timothy Spall ....................................... Peter Pettigrew
- Dave Legeno .......................................... Fenrir Greyback
- Ralph Inseson ........................................ Amycus Carrow
- Suzanne Toase ....................................... Alecto Carrow
- Rod Hunt .............................................. Thorfinn Rowle
- Lord John Paul Castrianni ....................... Yaxley
- Hero Fiennes Tiffin .................................. 11-year-old Tom Riddle
- Frank Dillane .......................................... 16-year-old Tom Riddle
Miscellaneous Castings
- Susie Shiner ............................................ Young Lily Evans
- Amelda Brown ......................................... Mrs Cole
- Ashley Whitehead ..................................... Orphan
- Taylor Triphook ....................................... Redhead twin
- Katie Head ............................................... Redhead twin
- Teresa Mahoney ....................................... Sofie (Boardroom -Opening Scene)
- Ben Shephard (‘Behind the Magic’ ) ............. Parent in the WWW joke shop
- Martin Ballantyne ..................................... Scary Face (Diagon Alley)
- Stephen Modell .......................................... Feather Wizard
- Chris Wilson .............................................. Yak Man - Daily Prophet
