Wallace, started his career with Edinburgh side Heart of Midlothian, making his debut in 2005, aged seventeen and moved to Glasgow to join Rangers seven years later. He remained with the club upon its demotion to the Scottish Third Division in 2012 and was awarded the club captaincy by the then manager Mark Warburton in 2015. Wallace has represented Scotland at both youth and full international level, collecting nine senior caps to date, his most recent against England in 2016.
Wallace signed professional terms with Heart of Midlothian in July 2004, having progressed from the Hearts youth team. Wallace made his debut in the 2004–05 season against Kilmarnock in the Scottish Cup and became a regular member of the first team squad although he found it hard to dislodge Takis Fyssas from the left back position. Wallace scored a goal in the cup tie against Kilmarnock.
In the summer of 2006 fellow Scottish Premier League club Dundee United had a loan bid for Wallace rejected. A month later, Wallace signed a five-year contract with Hearts. Wallace was made Hearts vice-captain at the start of the 2010–11 season, however, a month later while representing Scotland in a Euro 2012 qualifier against Liechtenstein, he suffered a cruciate ligament injury following a late challenge by Martin Stocklasa. Despite returning at the start of 2011, he continued to be blighted by injury and he made only seven appearances for the rest of the season.
On 22 June 2011, Hearts rejected a bid of £300,000 from Rangers, deeming it as derisory. A week later Rangers made an improved offer of £1m, which was also rejected. Hearts then placed a £3m price tag on Wallace. Wolverhampton Wanderers, then a Premier League side, had also expressed an interest in Wallace but did not make any offers. On 21 July 2011, a bid of £1.5m from Rangers was accepted by Hearts. Wallace signed a five-year deal with the club, becoming Ally McCoist's second signing of the summer.
Wallace made his Rangers debut in the Champions League qualifier on 26 July 2011, in a 1–0 defeat, at the hands of Swedish side Malmo. Wallace scored his first goal for Rangers on Christmas Eve 2011 in a 2–1 defeat to St Mirren. Four days later he thought he had scored again on his Old Firm debut, but the goal was not given as it judged not to have crossed the line. Wallace scored his second goal for the club on 25 March 2012, against Old Firm rivals Celtic, it was the third goal in a 3–2 win for Rangers.
Following the liquidation of The Rangers Football Club plc, Wallace opted to transfer his contract to the new company. At the beginning of the 2012–13 season Wallace was appointed vice-captain. On 14 September 2012, Wallace signed a new five-year contract with Rangers. Wallace was sent off during a game against Annan on 18 December 2012, conceding a penalty which was saved by Rangers goalkeeper Neil Alexander. This red card was rescinded on appeal. Wallace started the first game of the 2013–14 season in a 4–0 win over Albion Rovers in the Scottish Challenge Cup. Wallace played in the first league game of the season in a 4–1 win over Brechin City at Ibrox.
Wallace was the subject of much transfer speculation and both Nottingham Forest and West Ham United have been credited with interest in him. Forest manager Billy Davies made a pair of cash bids for Wallace in a bid to take him to The City Ground in January 2014, but each approach was turned down by the then Rangers chief executive Graham Wallace as the offers did not match the clubs valuation. On 21 July 2015, Wallace assumed the captaincy following the departure of previous captain Lee McCulloch. He was later named club captain by new Rangers manager Mark Warburton on 16 August. Wallace opened the 2015–16 season campaign by scoring a brace in Rangers' 3–1 home victory over St Mirren on 7 August 2015. Wallace was officially appointed captain on a permanent basis prior to Rangers' 5–1 win over Alloa Athletic at Recreation Park on 16 August 2015. On 5 April 2016, Wallace captained Rangers to a 1–0 home victory against Dumbarton to win the Scottish Championship and earn promotion to the top flight of Scottish football.
On 20 June 2016, Wallace signed a contract extension with Rangers until 2019. After signing, Wallace stated that he wanted to finish his career at Rangers. Wallace missed a 2016–17 Scottish League Cup match against Peterhead on 9 August 2016, which ended a run of consecutive competitive appearances at 69 that had begun in February 2015.
Alongside team-mate Calum Elliot, Wallace was an integral part of the Scotland U-19 team that reached the final of the 2006 UEFA U-19 Championships before narrowly losing to Spain. He started every match at left back. Wallace made his full international debut for Scotland in October 2009 playing in a friendly against Japan in Yokohama. He continued to feature for Scotland under manager Craig Levein, and in the Euro 2012 Qualifying match against Liechtenstein, Wallace suffered a serious injury to his posterior cruciate knee ligament.
Following Rangers' demotion to the Scottish Third Division, doubt was cast on Wallace's future international career by Craig Levein. However, on 31 January 2013, Wallace was named in the first squad of newly appointed Scotland manager Gordon Strachan. Wallace was named in the Scotland squad to face Croatia but late pulled out due to injury.
In August 2013, Rangers team mate David Templeton expressed his surprise at the omission of Wallace from the Scotland squad for the special challenge match with England. Manager Ally McCoist urged Wallace to use being overlooked for the international at Wembley as motivation to push into future Scotland squads. Wallace was recalled to the Scotland squad for the 2014 World Cup qualifiers with Belgium and Macedonia. After over two years out of the national team, Wallace was recalled in May 2016 for friendlies against Italy and France. Wallace subsequently pulled out of the squad, along with teammates Chris Martin and Alan Hutton, for unknown reasons.
On 27 March 2015, Wallace joined the coaching team at East of Scotland Football League side Tynecastle. Although his playing career will take precedence, Wallace aimed to combine both roles. He was in the away dugout as Rangers Under-20s played Tynecastle at Murray Park in July 2015.
In August 2006, Wallace was charged with a firearms offence. Three months later he admitted being in possession of an airgun and was fined £1,500. In May 2009, he was arrested and charged with breach of the peace outside an Edinburgh nightclub after allegedly threatening to shoot the doormen, however, this charge was later dropped and Wallace was fined £1,100 after admitting two charges of breach of the peace.As of 10 August 2017
Scottish Championship: 2015–16
Scottish Challenge Cup: 2015–16
Scottish League One: 2013–14
Scottish Third Division: 2012–13
Scottish Premier League Young Player of the Month: February 2009
Heart of Midlothian Players' Player of the Year: 2008–09, 2009–10
Rangers Player of the Year: 2013–14, 2015–16
Rangers Players' Player of the Year: 2012–13, 2013–14
John Greig Special Achievement Award: 2015–16
PFA Scotland Third Division Player of the Year: 2012–13
PFA Scotland Third Division Team of the Year: 2012–13
PFA Scotland League One Player of the Year: 2013–14
PFA Scotland League One Team of the Year: 2013–14
PFA Scotland Championship Player of the Year: 2015–16
PFA Scotland Championship Team of the Year: 2015–16