Sirola was born in Carteret, New Jersey to Croatian parents Anton, a carpenter and Ana (née Dubrovich), who ran a boardinghouse at 363 West 19th Street in Chelsea.

[10][9] During the 1960s he also appeared in a few films and television programs including Gunsmoke, Hang 'Em High, The Andy Griffith Show,[11][12] Chuka, Get Smart, The Man from U.N.C.L.E., Perry Mason, Strange Bedfellows and The Greatest Story Ever Told.

[6][13][14] His work on television commercials, for which he won over 20 Clio Awards, led to The Wall Street Journal nicknaming him “The King of the Voice-Overs” in 1970.

[6] Over the next 30 years Sirola appeared and guest-starred in numerous film and television programs including Hawaii Five-O; The Super Cops; Mannix; Kolchak: The Night Stalker; Wonder Woman; Quincy, M.E.

; Seizure; The Rockford Files; Spin City; Love, American Style; Charlie's Angels; Terrible Joe Moran; Diagnosis: Murder; The Ellen Burstyn Show and Washington: Behind Closed Doors.