Dowd began refereeing in local leagues in 1984, eventually officiating in the Staffordshire Senior League and Midland Football Alliance. He was appointed to The Football League list of assistant referees in 1992, before joining the League's full list of referees in 1997, aged 34. He was promoted to the Premier League list in 2001, his first match being a fixture between Fulham and Everton in December of that year. The 2014-15 season in English football was his fifteenth year refereeing in the top flight of English football. In 2006, Dowd was the fourth official at that year's FA Cup final at the Millennium Stadium in Cardiff. On 5 February 2011, Dowd was appointed to a Premier League fixture between Newcastle United and Arsenal, notable for becoming the first game in the league's history in which a team recovered from being 4-0 down to salvage a draw. Dowd issued a 50th-minute red card to Arsenal's Abou Diaby for violent conduct towards two Newcastle players following a challenge with Joey Barton. On 26 December 2011 Wigan Athletic's Conor Sammon was sent off by Dowd during his team's 5-0 defeat to Manchester United at Old Trafford. Wigan appealed the decision and the Football Association rescinded the red card three days later. After missing the whole of the 2015-16 season due to injury the PGMOL announced Phil Dowd had retired.
On 28 February 2010 Dowd refereed the League Cup final between Manchester United and Aston Villa at Wembley Stadium. In the fifth minute of the match, Dowd deemed Manchester United's Nemanja Vidić to have fouled Aston Villa's Gabriel Agbonlahor in the penalty area. Whilst Dowd did award Villa a penalty kick, he elected not to punish Vidić; some commentators felt the offence qualified as a professional foul and therefore warranted a red card. United overturned Villa's early penalty to ultimately win the match, and trophy, 2–1.
Dowd officiated the 2011 FA Community Shield on 7 August 2011 between Manchester City and Manchester United, also the 160th Manchester derby, at London's Wembley Stadium. United won the match 3-2 with a last-minute winner courtesy of Nani. Dowd issued seven yellow cards during the course of the game.
Dowd refereed the 2012 FA Cup Final between Chelsea and Liverpool, at Wembley Stadium on 5 May 2012. He was assisted by Stuart Burt and Andrew Garratt and Mike Jones was the fourth official. Dowd described his appointment to the Cup final as an "honour and privilege". The fixture took place on the third anniversary of the death of his father, whom Dowd said had always hoped to see his son referee a final of the FA Cup.