In his youth, Sealy studied piano with Daisy Peterson Sweeney, Professor Boyce, and Bob Langlois in Montreal; later he was pupil of Darwyn Aitken in Toronto. Sealy began his career during the late 1950s in jazz groups and/or show bands with René Thomas, Bob Rudd, Benny Winestone, Walter Bacon, and others throughout Quebec. Moving in 1967 to Halifax, he served as music director or consultant for several CBC TV series ('Music Hop' 1967-9, 'Roundabout,' 'Student Showcase,' etc), played organ in the Unusuals (an R&B trio with Charles 'Bucky' Adams, tenor saxophone; Chuck Cornish, French horn, drums and vocals), and was a pianist in local studio orchestras and hotel lounges.

In 1976 Sealy went to Toronto where he has worked extended engagements in jazz rooms and lounges (eg, intermittently 1980-3 at Errol's) and served as musical director for a succession of musicals through the 1980s, including Spring Thaw, Indigo, Ain't Misbehavin', More Sweet Reason, One More Stop, Madame Gertrude and Lady Day at Emerson's Bar and Grill, taking acting roles in several.

Sealy has written scores and/or songs for TV and film, and several themes for jazz group. Of the latter, Sealy has recorded Early Morning Blues, Dumpling, Clear Vision, Playa Caliente, Fat Cat and Distant Shores. An efficient jazz pianist whose style continues to show the influence of his early models, Oscar Peterson and Horace Silver, he has accompanied several leading US musicians in their Canadian appearances, including Buddy DeFranco, Milt Jackson, Sonny Stitt, and Joe Williams at Pepe's in Halifax. In 1979 he toured in the USA with David Clayton-Thomas and Blood, Sweat & Tears.