Lawrence never played league football. He turned out at non-league level for Croydon, Carshalton Athletic and Sutton United. He got his first managerial appointment at Plymouth Argyle as caretaker. He later worked as a coach at Lincoln City, helping them win promotion from Division Four in the 1980 - 81 season.
Lawrence moved to Charlton Athletic as reserve-team manager, and was later promoted to full-time manager in 1982. During his first few years in charge, the club was in a poor financial situation and came close to going out of business in 1984, and even left its home ground, The Valley, in 1985. Despite this, Lawrence not only kept Charlton in the Second Division but gained promotion to the First Division in 1986, ending Charlton's 29-year absence from the top-flight. With limited resources, he kept Charlton at this level for four years, before being relegated in 1990. He remained in charge for a further season.
Before the start of the 1991 - 92 season, Lawrence moved on to manage Middlesbrough. Under his stewardship, Middlesbrough finished Second Division runners-up in his first season as manager and gained promotion to the new Premier League but they struggled in 1992 - 93 and were relegated at the end of the season. Lawrence remained in charge until the end of the following season, his departure being confirmed on 2 May 1994. Upon leaving he helped young chairman Steve Gibson contact his replacement Bryan Robson.
Lawrence joined Bradford City at the beginning of the 1994 - 95 season. After a mid-table finish in his first season, Bradford were challenging for promotion in his second season in charge before he left to manage struggling Luton Town in the division above. Lawrence was unable to save Luton from relegation to Division Two at the end of the 1995 - 96 season, which saw them replaced by former club Bradford. He remained in charge at Kenilworth Road until 2000 when he was sacked by the new incoming Luton chairman, Mike Watson Challis, and replaced with former Luton fans favourite, Ricky Hill. His time at Luton is not fondly remembered by Luton fans, who didn't agree with Lawrence's assertion that the club should be happy to be playing Division Two (now League One) football.
He made a quick return to management shortly after the beginning of the 2000 - 01 season with Division One side Grimsby Town. They avoided relegation and made a reasonable start to the 2001 - 02 season, and caused an upset in the League Cup third round by knocking out holders Liverpool 2 - 1 after extra time at Anfield, scoring with a Phil Jevons wonder-goal in the last minute. However he was sacked later in the season after Grimsby dropped to the bottom of the table.
During the opening weeks of the 2001-02 season, his Grimsby side had briefly led Division One, sparking hopes that he could repeat the promotion success he achieved at Charlton Athletic and Middlesbrough with a much smaller club. However, these hopes were quickly extinguished as Grimsby's form plunged.
After a short while out of the game he joined Division Two side Cardiff City as a consultant. Owner Sam Hammam had made it clear to manager Alan Cork that he expected back-to-back promotions, which it did not look like Cork was going to deliver. Eventually Cork was sacked, and Lawrence took over the manager's chair. In his first full season in charge, Lawrence took Cardiff to promotion after beating Queens Park Rangers in the 2003 Football League Second Division play-off final. He remained at Ninian Park for a further two years before being shunted aside in May 2005.
After acting as a consultant at Cardiff for a while, he was appointed Director of Football at Bristol Rovers, working alongside coach Paul Trollope in a two-tier managerial structure. In the pair's first full season in charge, Bristol Rovers won promotion into League One after winning the League Two play-offs. He remained in this position until leaving the club on 12 May 2010, with their League One status still intact.
In August 2010 Lawrence joined non-league Carshalton Athletic in a football consultancy role, assisting manager Mark Butler. Four months later he was appointed technical director at Hereford United in League Two, to assist new manager Jamie Pitman.
On 20 January 2011, he was appointed assistant manager at Crystal Palace, to support new rookie manager, Dougie Freedman.