Webster came through Bray Wanderers youth setup and signed a contract with Eddie Gormley's first team squad in February 2008 whilst still playing for the reserve side in the A Championship. His first senior appearance for the club came on 5 May 2008 when he came on as a substitute for Paddy Kavanagh with 9 minutes left of a 1– win over Shamrock Rovers at the Carlisle Grounds in the League Cup. His only other appearance that season came on 16 July 2008 when he started in a friendly against English League One side Millwall, in a 1–0 loss for Wanderers. The 2009 season proved to be Webster's breakthrough season in senior football as he became an established regular at centre back for Bray. The first goal of his career came on 14 August 2009 when he scored in a 2–0 win over Tralee Dynamos in the FAI Cup. Webster's first League of Ireland goal came on 19 September 2009 when he opened the scoring in the 16th minute in a vital league game against Shamrock Rovers at Tallaght Stadium as his side fought to fight off relegation. Bray ended the season bottom of the table and lost out to Sporting Fingal in the final of the Promotion/Relegation Playoffs meaning they would be relegated to the League of Ireland First Division however they kept their top flight status as Cork City and Derry City were both expelled from the League of Ireland Premier Division for financial reasons. It was a mixed season for Webster and Bray in 2010 as they were runners up in the Leinster Senior Cup but again struggled to fight off relegation, taking them right up until the Promotion Relegation Playoff final as they beat Monaghan United 7–6 on penalties to defy all odds and stay up once again. During the season he also had the opportunity to play against top sides like Middlesbrough and Villareal CF, featuring some of the 2010 World Cup winning Spain side. Webster only managed 19 appearances the following season in 2011 which was not helped by injuries but it was a successful season for the team as they finished in a respectable 6th place earning 51 points and qualifying for the following season's Setanta Sports Cup. The club's stay in the 2012 Setanta Sports Cup was short lived however as they were knocked out by Glentoran at the first hurdle with Webster featuring in both games. Webster featured in 27 games over the course of the season as his side once again stayed out of the Playoffs as they finished a comfortable 5 points ahead of Dundalk. Two more seasons of relegation battles followed for Webster and Bray as they beat Longford Town in the final of the 2013 Playoffs, before avoiding the playoffs in 2014 by a single point ahead of UCD.
Shamrock Rovers
It was announced on 26 November 2014 that Webster had been signed by Shamrock Rovers manager Pat Fenlon on a 2 year contract, alongside Gavin Brennan, Barry Murphy and Craig Hyland. Webster was a mainstay in defence for Rovers in his first season as he featured in 30 games in all competitions, including all 4 UEFA Europa League games against Progrès Niederkorn of Luxembourg and Odds BK of Norway. The 2016 season was a poor one for Webster and Rovers as they were embarrassing beaten 5–0 at home in the FAI Cup Quarter Final, knocked out at the first hurdle of the UEFAEuropa League to RoPS of Finland and in the league they finished 4th, a massive 22 points off champions Dundalk. The poor form in the previous season resulted in Pat Fenlon being sacked by the club but his replacement Stephen Bradley offered Webster a new contract which he signed on 29 November 2016. Bradley showed a lot of faith in Webster over the season, playing him a total of 39 times across all competitions including all 4 UEFA Europa League games as the Hoops knocked out Iceland's Stjarnan before being beaten twice by FK Mladá Boleslav of the Czech Republic, in a season which they finished in 3rd place in the league as well as being runners up in the 2017 League of Ireland Cup to Dundalk, who also knocked them out of the FAI Cup, after a Semi-final replay at Tallaght Stadium. On 14 November 2017 it was announced that Rovers would not be offering Webster or Ryan Connolly a new contract for 2018.
Waterford
After 95 appearances for Rovers in all competitions, Webster signed for newly promoted Waterford under manager Alan Reynolds on 29 November 2017. Webster played a total of 31 times for the Blues as they finished in 4th place, securing a UEFA Europa League place for the following season as they finished 9 points ahead of nearest challengers St Patrick's Athletic.
St Patrick's Athletic
On 14 November 2018, it was announced that had signed for Dublin club St Patrick's Athletic, becoming new manager Harry Kenny's second signing. Upon signing, Webster sited one of his reasons for joining the Saints being that he was at a stage of his career in which he wanted to win medals. He made his debut for the club in a 1–0 win over Cork City on 15 February 2019, the opening night of the season. During the season, it was announced that Pat's would be playing UEFA Europa League football at the expense of his old club Waterford after they failed to meet UEFA's '3 year rule'.
Finn Harps
Webster was announced as having signed for Finn Harps on a one year deal on 28 December 2019.
Career statistics
Professional appearances – correct as of 19 February 2020.
