[2] He began his senior football career at Rangers, followed by a loan spell at Third Division outfit Scunthorpe United, scoring 25 goals.

[3] On 7 July 2004, MacLean joined Football League One club Sheffield Wednesday for an undisclosed fee, believed to be around £125,000, and signed a three-year deal.

MacLean sustained another injury setback in August 2006 after scoring in a 1–1 draw against Burnley, but made a comeback a month later in the defeat to Derby County.

On 22 June 2007, it was announced that MacLean had signed for Sheffield Wednesday's Championship rivals Cardiff City, after failing to agree a new contract at Hillsborough.

[6] MacLean began the season as Cardiff's leading striker after Robbie Fowler was deemed not fit enough to play in some of the team's opening games.

Things continued to get worse for him as he suffered ruptured ankle ligaments in a reserve match against Plymouth Argyle, which was expected to rule him out until December.

After his return, he made mostly late substitute appearances, with just three starts for Cardiff – in a 2–0 defeat against Charlton Athletic, a 2–2 draw with Watford, and a 3–1 win against Chasetown in the FA Cup.

After finding himself out of favour at Cardiff, MacLean signed a three-and-a-half-year deal with Plymouth Argyle on 18 January 2008, reuniting with former Sheffield Wednesday manager Paul Sturrock.

The incident was subject to an internal enquiry by the club and could have led to MacLean's contract being terminated, but two days late Johnson said that he was satisfied the gesture was just an "over-exuberant" celebration.

After Yeovil's game against Carlisle United, Johnson explained that he had received an approach from Robins manager Mark Yates, and with MacLean struggling to get minutes on the pitch at present, the Glovers boss told BBC Somerset that he could see it as suiting all parties.

However, he suffered a dislocated elbow during the match and was out of action for about six weeks[21] He marked his recovery from injury,[22] in a 1–1 draw against Inverness Caledonian Thistle on 27 October.

[26] After the match, MacLean quoted "I tried to go for power [with my penalty] but the keeper has guessed right"[27] In the newly founded Scottish Premiership at the top of the Scottish Professional Football League, MacLean scored four goals between late September and mid-October against Partick Thistle, Inverness Caledonian Thistle and St Mirren.

[30] Weeks after signing a new deal, MacLean started in the Scottish Cup final, alongside his striking partner, Stevie May.

With ten minutes remaining and St Johnstone winning 1–0, MacLean scored the second goal in the final after "he slid in to challenge Cierzniak before turning the ball over the line while grounded."

[32] On 24 July 2014, MacLean made amends for his missed penalty in the Europa League a year earlier by emphatically scoring the first penalty in the Europa League 2nd Round Qualifier against FC Luzern at McDiarmid Park, after the match finished 1–1, 2–2 on aggregate, with MacLean scoring for the Saints in the first leg a week earlier in Switzerland.

[40] Unable to recuperate scoring goals throughout the season, MacLean, nevertheless, helped the club qualify for the Europa League for 2015–16: the third year running.

[47] MacLean was sacked by St Johnstone on 29 October 2023, after a run of nine games without a win left them bottom of the 2023–24 Scottish Premiership table.