Michael Wilcox abandoned his teaching career to become a full-time playwright in 1974. From 1977 to 1978 he was resident playwright at the Dovecot Arts Centre, Stockton-on-Tees and in 1980 he became resident playwright at the Traverse Theatre, Edinburgh. 

Theatre credits include: MRS. STEINBERG AND THE BYKER BOY (Bush, 2000); ROCK’N’ROLL AND BARBIROLLI (Snap Touring Co, 1999); TIME WINDOWS (Westcliff-on-Sea, 1992); GREEN FINGERS (Northern Stage/Live Theatre, 1990); MASSAGE (Lyric, Hammersmith, 1986); 78 REVOLUTIONS (Traverse/Lyric, Hammersmith,1984); LENT (Lyric, Hammersmith, 1983); RENTS (Traverse ,1979, numerous revivals); ACCOUNTS (Traverse/Riverside Studios, 1981; Hudson Guild Theatre, New York, 1983); PHANTOM OF THE FELLS (Live Theatre Co, 1977); PIONEERS, MOWGLI and THE BLACKETTS OF BRIGHT STREET (Dovecot Arts, 1977-78). LENT and ACCOUNTS have been broadcast on BBC Radio.

In 1995 he collaborated with Jeremy Sams to write a new libretto for Chabrier's THE RELUCTANT KING for Opera North; CULLERCOATS TOMMY (with composer Eddie McGuire) was commissioned by Northern Sinfonia and Northern Stage (1993) and in 1990 he was librettist for John Metcalf's TORNRAK (WNO). His book, BENJAMIN BRITTEN’S OPERAS (Absolute Press 1997),