Impressing at part-time youth manager Lyall was offered the role on a full-time basis in 1967. He rose through the coaching ranks at Upton Park to succeed Ron Greenwood as team manager in September 1974, managing West Ham for 15 years (1974–1989). In 1975, at the end of his first season as manager, West Ham won the FA Cup final and reached the final of the European Cup Winners' Cup the following year, losing 4–2 to Anderlecht. However, West Ham slipped down to the Second Division in 1978. Lyall attempted to rebuild the side and made significant purchases in Phil Parkes, £565,000 from Queens Park Rangers, a world record for a goalkeeper and Ray Stewart from Dundee United for £430,000, a British record for a teenager. West Ham returned to the First Division in 1981 winning the title by a thirteen-point margin.