Hourihane signed from school for Sunderland, who were then in the Premier League, then chose to move to Championship Ipswich when he was nineteen, although he failed to make a first team appearance for either side. A year later he signed for League Two Plymouth Argyle, where he spent three seasons before joining Barnsley for £250,000. Here he had two successful visits to Wembley within two months, winning the Football League Trophy in April 2016 and the League One play-offs the following month. Hourihane was named Championship Player of the Month for August and subsequently linked with Villa as the transfer window opened, signing during the last week of January as part of a spending spree that saw six players arrive within eleven days.

Hourihane’s Villa debut came in the 3-0 reverse at Brentford and he played in four subsequent defeats before picking up an injury in training. He returned for a 2-0 win at home to Bristol City and scored Villa’s second goal – a close-range tap-in, unlike many of his subsequent strikes. Hourihane was in and out of the side for the rest of the season, mainly to accommodate the return of the mercurial but injury-prone Jack Grealish. With thirteen starts and one goal Hourihane had scarcely got Villa Park buzzing during the second half of a generally disappointing season in which the team finished in the bottom half of the Championship, but he had settled in well, worked hard and shown that he could hit a ball accurately.

Hourihane missed the opening day draw with Hull City at the start of 2017-18 and was a substitute during a defeat at Cardiff but from then on was a virtual ever-present in a side that stayed in touch with the pace-setters without ever looking as though they could gain automatic promotion. A hat-trick as Villa beat Norwich City included two long-range efforts and as the season progressed Hourihane’s shooting prowess was a feature of Villa’s attacking play. The fiftieth league goal of his career came in a 2-1 win over Nottingham Forest and several others were the prelude to his first entry into Villa Park folklore. Scoring against Birmingham City is always a good way to win over the fans, especially with a 25-yard piledriver in a routine 2-0 victory. Villa eventually finished fourth and qualified for the play-offs with ease.

The play-off final against Fulham saw none of the team shine but despite the defeat condemning Villa to a third season in the Championship, and as it turned out almost going out of business, Hourihane could be proud of his individual contribution. He had played in 45 games in all competitions and netted eleven goals. His fee, modest in comparison to some Villa were paying at this time, was already looking money well spent.

Not only did the club face an uncertain future at the start of the new season, for Conor there was an extra problem in the shape of John McGinn, newly-arrived from Hibernian and a rival for the Irishman’s midfield position. Hourihane played in the opening-day win over Hull City but made way for McGinn for the next game. He came back into the starting line-up against Rotherham and kept his place in a run that included the infamous 3-3 draw at home to Preston that led to the departure of Steve Bruce and the following match, where managerless Villa lost at Millwall. A squad player early in Dean Smith’s reign, Hourihane returned for a home win against Bolton and his goals over the following weeks helped Villa move to within three points of the play-off places before another poor run of form saw them drop to eleventh, eight points adrift of the promotion zone with twelve games remaining.

What came next was the stuff of dreams. Hourihane scored twice in the 4-0 win over Derby County, the game that saw the return of Jack Grealish to the Villa side and the start of the remarkable run of ten successive league victories. He also scored the second in a 2-1 win at home to Bristol City during the record-breaking run that led the club to a final fifth-place finish.

Villa found themselves against their oldest rivals in the play-off semi-finals. Dean Smith called dropping Hourihane for the first leg “a massive decision” and it seemed his choice might prove fatal when Glen Whelan’s error gave Albion an early lead. Hourihane replaced his fellow Irishman midway through the second half and when Jack Grealish found him unmarked twenty yards out, many in the crowd were already celebrating before the ball had left his boot. Villa took a 2-1 lead to the Hawthorns, where they lost 1-0 on the night, booking a second successive appearance in the finals after a penalty shoot-out. Hourihane took Villa’s first and proved as accurate from twelve yards as he had regularly from further out.

The final against Derby was an anti-climax after the dramas of the previous three months. Hourihane, anchoring Villa’s three-man midfield, was as professional as the rest of the side in a 2-1 win that only looked problematic during the final few minutes where Derby pulled back a goal and attacked desperately. During a memorable and ultimately successful season Hourihane had played in 48 games and scored nine times.

The reward for helping the club win promotion was a new three-year contract, although with Villa back in the Premier League and their billionaire owners spending heavily, Hourihane found the competition for places even greater. He started the opening day defeat at Spurs, got a goal in Villa’s 5-1 win at Norwich (which gave him the rare distinction of having scored in all four levels of the English league system) then got Villa’s opener in a 2-0 win against Newcastle. A run of poor form saw the team dropping into the bottom three, but a Boxing Day win at home to Norwich, where Hourihane scored against the East Anglian side yet again, provided some respite. This was to prove his last goal at Villa Park for the club.

Although no longer a first team regular in the league, Hourihane featured heavily in the run that took Villa to an unlikely League Cup final appearance. He played in every game up to the semi-final against Leicester, scoring twice in a 6-1 win against Crewe in the first round, getting another away at Brighton and one more in the 5-0 win over a weakened Liverpool in the quarter-final. Hourihane came on during the dramatic 2-1 win at home to Leicester and a twenty-minute substitute appearance in the 2-1 defeat against Manchester City meant he had appeared in five Wembley finals in four years, in four different competitions.

After the league programme restarted Hourihane was back in favour as Villa’s poor form continued. They had lost the four games played before the league programme had been curtailed and after the restart could only get two points from the first six games. They were seven points from safety with four fixtures remaining and no club had ever avoided relegation from the Premier League in such a situation, yet for the second successive season Villa were transformed when all seemed lost. Hourihane laid on both goals in a win at home to Crystal Palace that provided a glimmer of hope and his free-kick led to the opener in a 1-1 draw at Everton in the following match. Villa’s first win at home to Arsenal for 22 years followed and survival was assured with a draw at West Ham. Hourihane had started 23 games, made eleven substitute appearances and scored seven times during another roller-coaster season at Villa Park.

With Villa safe for another season, there would be further summer spending. Hourihane started the opening game, a win at home to Sheffield United, came on as a late substitute in a League Cup third round win against Bristol City then played in a comfortable 3-0 victory at Fulham where he scored one and made the third from another free-kick. Despite this performance Conor was dropped for the next league game to accommodate loan arrival Ross Barkley. This was the legendary 7-2 win over Liverpool, and naturally enough Barkley kept his place in the side for the next month, despite failing to reproduce the promise of his debut.

Hourihane started at home to West Ham and his withdrawal after 76 minutes was the last time he played for the Villa. In January 2021 Hourihane moved to Championship side Swansea City on loan for the rest of the season, playing in nineteen games and scoring five goals. He spent 2020-21 at another Championship club, Sheffield United, where he played 21 games and scored once. With his Villa contract expired he signed for League One Derby County in the summer of 2021. He had played in 151 games for Villa and scored 29 goals, including some of the most spectacular and important ones Villa Park had witnessed for many years.

In the summer of 2023 he was named as Derby team captain and it was also announced that he would be working with the Villa Academy, coaching the under-16 teams. In the following summer he left Derby to return to Barnsley, then back in League One, as player-coach. In March 2025 he was appointed team manager until the end of the season.