During his career there, he had loan spells at Haka and Ipswich Town before joining West Ham United in 2003 and then Aston Villa in 2007.

He caught the eye of West Ham fans when he scored for Forest in an FA Cup Third Round clash at Upton Park on 4 January 2003.

He scored 14 league goals, including the first top flight hat-trick of the season in a 4–0 home victory against Aston Villa[8] and also put West Ham in front after just 52 seconds against Manchester United[9] also at Upton Park.

[10] Harewood collected an FA Cup runners-up medal with West Ham that season, after they lost on penalties following a 3–3 draw with Liverpool.

[16] Harewood said, "I was all set to sign [for Wigan] on the Monday when I got a phone call saying Martin O'Neill wanted to speak to me.

[15] Harewood scored his 100th career league goal as Aston Villa beat Blackburn Rovers 4–0 at Ewood Park on 28 November 2007.

Harewood continued to be a fringe player at Aston Villa throughout the winter and eventually scored his second goal in the 2–2 draw with Liverpool in January.

Despite his good performances from the bench Martin O'Neill continued to use him as a "super-sub" (albeit he did start against Manchester United due to injury troubles).

After the arrival of Emile Heskey at Villa Park in January 2009, newspapers started speculating that his time at the club was coming to an end, with rumours of a move to Stoke,[17] Sheffield United and Middlesbrough.

Harewood joined up with newly promoted Premier League side Blackpool in early August 2010 and soon entered talks with the club about a permanent deal.

[29] Two days later he scored twice as Blackpool marked their Premier League debut with a 4–0 win over Wigan Athletic at the DW Stadium – their first top division game since 1971.

[34] He made his debut on 9 July in a 2–1 home victory against Yanbian Baekdu Tigers, coming on as a substitute for Wen Chao in the 55th minute.

Harewood scored 4 goals in 10 appearances as Guangzhou R&F finished second place in the League One and won promotion back to the top flight at the first attempt.

[38] On 20 July 2013, Harewood featured as a trialist for Bristol City in a pre-season friendly against Forest Green Rovers at The New Lawn.

[46] In February 2008, Harewood rejected a call-up to Barbados for the two-legged 2010 FIFA World Cup qualifier against Dominica, deciding to concentrate on his club football with Aston Villa.

[48] In November 2021, Harewood declared his desire to enter management, whilst at the same time expressing concern over player power in the dressing room.