Williams played as a goalkeeper making 271 appearances in the English Football League, including 161 for Tranmere Rovers, also representing Crewe Alexandra, Stockport County, Bury, and Rochdale.

He has since played for Scottish clubs Inverness Caledonian Thistle, Hamilton Academical and Dunfermline Athletic, and in the United States for Indy Eleven.

Williams joined Crewe Alexandra after impressing during a trial period when he had his spells at Premier League clubs Manchester United and Liverpool and was signed on scholarship forms in 2003.

[15] After making his debut in a 1–1 draw with Huddersfield Town on the opening day of the 2008–09 season,[16] Williams soon established himself as County's No.1, however in October 2008, he lost his first team place to on-loan keeper Fraser Forster.

[18] His performance saw also him being linked with a move to Premier League side Blackburn Rovers and Newcastle United and the club may sell him, as they faced financial problems.

[26] On 28 October 2010, Williams joined local rivals Bury on a two-month-long emergency loan deal to replace the injured Cameron Belford.

[35] Despite suffering a thigh injury in the pre-season friendly,[36] Williams made his competitive club debut on the first day of the 2011–12 season, starting the Football League match against Chesterfield.

[38] Williams established himself as a first choice goalkeeper at Tranmere Rovers and his impressive display led him being praised by Manager Les Parry.

Upon discovering that he would not start the game, he returned to Tranmere Rovers line-up less than 24 hours after sitting on the national side's substitutes bench and played in a 3–2 win over Yeovil Town on 13 October 2012.

[44] By the end of October, Williams made a good display, where he conceded fourteen goals in fifteen games and kept a clean sheet at least six times.

[45] During a period of heavy snowfall in January 2013, an away fixture at Brentford was briefly stopped as Williams was pelted by snowballs thrown from the home supporters.

[53][54] Despite this, Williams' continued to impress and was nominated for Sky Bet League 1 Player of the Month award for February as a result of his good performance.

[66] His league debut came on 1 August, as the team began their season with a 0–1 home loss to Motherwell in which he saved a penalty from Scott McDonald.

[70] Williams was loaned to Scottish Championship club Dunfermline Athletic in January 2020,[71] playing in 6 matches before the season was halted due to the COVID-19 pandemic.

[77] He took over as the team's number one goalkeeper and missed just one match in the qualifying round of the 2009 UEFA European Under-21 Championship as they finished top of their group before being beaten by England in the play-off.

[80][81][53][82] He finally made his debut on 13 November 2015 in a friendly against the Netherlands at Cardiff City Stadium, replacing Wayne Hennessey with 16 minutes to play and the score at 2–2, and conceded the winning goal from Arjen Robben.