Wycombe Wanderers Phillips signed for
Wycombe Wanderers at the age of eight when he was spotted playing in a
five-a-side tournament. Having progressed through Wycombe's junior sides, he made his first team debut as an 82nd-minute substitute, a month after his seventeenth birthday, on 26 April 2008 in a 1–0 defeat to
Notts County, the penultimate game of the 2007–08 season. His first start came a week later in the 2–1 win over
Bradford City at
Adams Park, in which he was voted
man of the match by the Wycombe supporters. After breaking into the first team during the previous season, Phillips signed his first professional contract in July 2008, a year before the end of his youth team scholarship. His first goal for the Chairboys came on 10 November 2008 in the 4–1 away win over
AFC Wimbledon in the
First round of the
2008–09 FA Cup. His first league goal came on 6 December in the 3–2 away defeat to
Aldershot Town. Phillips went on to make a massive contribution to the Chairboys promotion from
League Two in the 2008–09 season, becoming a regular on either the left or right wing, impressing with his ability to take on defenders and to cut inside. He was also won the club's two "Young Player of the Year" awards at the end of the season as well as the League Two "Apprentice of the Year". Phillips was given the number 18 shirt for the
2009–10 season and continued his good form from the previous season, playing on either flank. In total, Phillips made 87 league and cup appearances for Wycombe, scoring nine goals.
Blackpool Phillips signed for
Premier League club
Blackpool on 31 August 2010 in an original £350,000 deal, rising to £700,000 for achieving specific criteria. Manager
Ian Holloway stated that he had been tracking Phillips for "a long time", saying of him, "Young Matty looked really exciting at times. He was skipping past people like they weren't there and now I've got to get him in our shape and working within it. He is definitely one for not only the long-term future but the immediate future. I am getting quite excited about what he might be able to produce." Phillips' first team debut came on 25 September in the 2–1 home defeat to
Blackburn Rovers. Phillips came on as a substitute in the 84th minute, making an instant impact, scoring his first ever Premier League goal just seconds later. After the match Ian Holloway praised Phillips saying, "I thought he was terrific. He's only 19 and he's someone who I think will have a good future. He played in a different role and smacked one in like that. Hopefully there is a lot, lot more to come from that boy because he has got some bits and pieces that would grace any level of football." Of his debut and goal Phillips said: "I've dreamt of playing in the Premier League since I was a kid, so to play Premier League football is one thing, but to go out there and make a mark on it is another, so I'm delighted." He made his full-debut against
Aston Villa at Villa Park, a performance which led manager Ian Holloway to describe him as "at times un-markable". After a successful spell on loan at
Sheffield United, Phillips scored a hat-trick in Blackpool's
Boxing Day 3–1 victory at
Barnsley. He scored another hat-trick two weeks later, this time against
Fleetwood Town in the FA Cup third round. Later that month Blackpool rejected a bid from
Cardiff City, believed to be around £800,000, for the winger. In the week before the start of the
2012–13 season Blackpool rejected a £5 million bid for Phillips from newly promoted Premier League side
Southampton. He then put in a transfer request, and after being left out of the opening day victory over
Millwall on 18 August, he returned to action three days later, scoring the winning goal in a 2–1 home victory over
Leeds United.
Sheffield United (loan) With first-team opportunities proving limited, Phillips agreed a months loan to
Sheffield United in October 2011, making his début in the
Steel City Derby a few days later. Phillips had a major impact in his month spell, scoring six goals in six appearances for the
South Yorkshire club before returning to Bloomfield Road.
Queens Park Rangers On 23 August 2013, Phillips signed for
Queens Park Rangers on a four-year deal for an undisclosed fee and was handed the number 7 shirt. He made his debut for the club on 14 September, coming on as a first-half substitute for
Junior Hoilett against
Birmingham City. He scored his first goal for Queens Park Rangers on 3 December, netting the final goal in a 3–0 win over
Bournemouth. His second goal for the club came eleven days later, when he scored the first in a 2–0 win over his former club
Blackpool. His third goal was an equaliser against Doncaster Rovers in a league match at Loftus Road which QPR went on to win 2–1. Phillips suffered a broken leg against
Burnley on 1 February 2014 which ruled him out for the remainder of the season, however QPR won promotion in the
2014 Championship play-off final against
Derby County. Phillips was fit again for QPR's first game back in the Premier League, a 1-0 loss at home to
Hull City. He struggled for game time initially but played almost every minute in the league after the resignation of
Harry Redknapp on 3 February 2015. On 14 March, Phillips scored "a goal of the season contender" from 40 yards out in a 3-1 loss at
Crystal Palace.
West Bromwich Albion On 6 July 2016, Phillips joined
Premier League side
West Bromwich Albion on a four-year deal. Phillips got his first league goal in a win against reigning Premier League Champions
Leicester City. He finished the game with an assist and the winning goal in the 2–1 win. Phillips continued his goal scoring exploits in the next game against
Burnley F.C. He opened the scoring in the fourth minute and also set up a goal for Albion captain
Darren Fletcher, helping the team to establish a 3–0 first half lead, in a game which ended as a 4–0 win. On 31 December he scored and set up
Hal Robson-Kanu's first Albion goal in a 2–1 win over Southampton. He set up more goals for
Chris Brunt and
Gareth McAuley in a 3–1 win over
Hull which took his tally up to 8 assists for the season. On 5 August 2021, Phillips signed a contract extension until the summer of 2024. On 22 May 2024, the club announced he would be leaving in the summer when his contract expired.
Oxford United On 1 August 2024, Phillips signed for newly promoted Championship club
Oxford United on a free transfer. On 13 August, Phillips made his debut for the club, as well as scoring his first goal, in a 2–0 win against
Peterborough United in the
EFL Cup. On 2 February 2026, Phillips left Oxford by mutual consent.
Stevenage On 13 February 2026, Phillips signed for
Stevenage for the remainder of the season. ==International career==