United struggled to replace Busby, and the team struggled under Wilf McGuinness in the 1969-70 season, finishing a disappointing 8th, and following a poor start to the 1970-71 season, McGuinness was demoted back to the position of reserve team coach. Busby was coaxed back to the club, albeit only for six months. Results got better with Busby's guidance, but he finally left the club for the last time in the summer of 1971. In the meantime, United had lost a number of high-profile players such as Nobby Stiles and Pat Crerand.
Despite approaching Celtic's European Cup-winning manager, Jock Stein, for the manager's job - Stein had agreed a verbal contract to join United, but pulled out at the last minute - Frank O'Farrell was appointed as Busby's successor. However, like McGuinness, O'Farrell only lasted less than 18 months, the only difference between the two being that O'Farrell reacted to the team's poor form by bringing in some fresh talent, most specifically Martin Buchan from Aberdeen for £125,000. Tommy Docherty became manager at the end of 1972. Docherty, or "the Doc", saved United from relegation that season but United were relegated in 1974, by which time the golden trio of Best, Law and Charlton had left the club. Denis Law had moved to Manchester City in the summer of 1973, and ended up scoring the goal that many people say relegated United, and politely refused to celebrate the goal with his team mates. Players like Lou Macari, Stuart Houston and Brian Greenhoff were brought in in to replace Best, Law and Charlton, but none could live up to the stature of the three that came before.
The team won promotion at the first attempt, with a young Steve Coppell making his début towards the end of that season, having joined from Tranmere Rovers, and reached the FA Cup final in 1976, but were beaten by Southampton. They reached the final again in 1977, beating Liverpool. In spite of this success and his popularity with the supporters, Docherty was sacked soon after the final when he was found to have had an affair with the physiotherapist's wife.
Dave Sexton replaced Docherty as manager in the summer of 1977, and made the team play in a more defensive formation. This style was unpopular with supporters, who were used to the attacking football preferred by Docherty and Busby. Major signings under Sexton included Joe Jordan, Gordon McQueen, Gary Bailey and Ray Wilkins, but Sexton's defensive United failed to break out of mid-table obscurity, only once finishing in the top two, and only reached the FA Cup final once, losing to Arsenal. Because of this lack of trophies, Sexton was sacked in 1981, even though he won his last seven games in charge.
He was replaced by the flamboyant Ron Atkinson, whose extrovert attitude was reflected in the clubs he managed. He immediately broke the British record transfer fee to sign Bryan Robson from his old club, West Brom. Robson would come to be touted in the future as United's best midfield player since Duncan Edwards. Atkinson's team featured new signings such as Jesper Olsen, Paul McGrath and Gordon Strachan playing alongside former youth-team players Norman Whiteside and Mark Hughes. United won the FA Cup in 1985, after reaching the final in 1983, and were overwhelming favourites to win the league in the 1985-86 season after winning their first ten league games, opening a ten-point gap over their rivals as early as October. The team's form collapsed, however, and United finished the season in fourth place. The poor form continued into the following season, and with United on the edge of the First Division's relegation zone by the beginning of November 1986, Atkinson was sacked.
Alex Ferguson era
Alex Ferguson arrived from Aberdeen to replace Atkinson and guided the club to an 11th place finish. The following season (1987-88), United finished second, with Brian McClair becoming the first United player since George Best to score twenty league goals in a season.
However, United struggled throughout the next two seasons, with many of Ferguson's signings not reaching the expectations of the fans. Alex Ferguson was reportedly on the verge of being sacked at the beginning of 1990 but a Mark Robins goal gave United a narrow 1-0 win in the third round of the FA Cup over Nottingham Forest. This kept the season alive, and the team went on to win the competition, beating Crystal Palace in a replay in the final.
United won the European Cup Winners' Cup in 1990-91, beating that season's Spanish champions Barcelona in the final, but the following season was a disappointment as a late season slump saw them miss out on the league to rivals Leeds United. Meanwhile in 1991, the club floated on the London Stock Exchange with a valuation of £47 million, bringing its finances into the public eye.
The arrival of Eric Cantona in November 1992 provided the crucial spark for United, and blending with the best of trusted talent in Gary Pallister, Denis Irwin and Paul Ince, as well as budding stars like Ryan Giggs, they finished the 1992-93 season as champions for the first time since 1967. They won the double (the league and the FA Cup) for the first time the following season, aided by the capture of Roy Keane, a determined midfielder from Nottingham Forest, who would go on to become the team captain. In the same year, however, the club was plunged into mourning following the death of legendary manager and club president Matt Busby, who died on 20 January 1994.
In 1994-95, Cantona received an eight month suspension for jumping into the crowd and assaulting Crystal Palace supporter Matthew Simmons, who had given Cantona racial abuse as he left the field, in United's game at Selhurst Park. Drawing their last league match and losing to Everton in the FA Cup final left United as runners-up in both the league and FA Cup. Ferguson then outraged the supporters by selling key players and replacing them with players from the club's youth team, including David Beckham, Gary Neville, Phil Neville and Paul Scholes. The new players, several of whom quickly became regular internationals for England, did surprisingly well and United won the double again in 1995-96. This was the first time any English club had won the double twice, and the feat was nicknamed the "Double Double".
They won the league in 1996-7, and Eric Cantona announced his retirement from football at the age of 30. They started the following season (1997-98) well, but they finished in second place, behind the double-winning champions Arsenal.