Early years Mullan began playing
women's field hockey at
Dalriada School where her
PE teacher and hockey coach was
Bridget McKeever, a former
Ireland women's field hockey international. She also played for Ballymoney.
UCD Mullan started playing for
UCD in 2012. She was a member of the UCD teams that won the
Irish Senior Cup in 2014, 2017 and 2018. She scored UCD's third goal in the 2018 final when they defeated
Pegasus 4–0. Mullan was also a member of the UCD teams that won
Women's Irish Hockey League titles in 2013–14, 2016–17 and 2017–18. In 2017 UCD completed a treble when they also won the
EY Champions Trophy after defeating
Hermes-Monkstown in a
penalty shoot-out. Mullan has also played for UCD in the
2015 and
2018 EuroHockey Club Champions Cups.
Ireland international Mullan represented
Ireland at Under-17 Together with
Roisin Upton and
Emily Beatty, Mullan represented Ireland at the
2010 Youth Olympic Games. In March 2015 Mullan was a member of the Ireland team that won a
2014–15 Women's FIH Hockey World League Round 2 tournament hosted in
Dublin, defeating
Canada in the final after a
penalty shoot-out. She was also a member of the Ireland team that won the
2015 Women's EuroHockey Championship II, scoring in the final as they defeated the
Czech Republic 5–0. In January 2017 she was also a member of the Ireland team that won a
2016–17 Women's FIH Hockey World League Round 2 tournament in
Kuala Lumpur. She again scored in the final as Ireland defeated
Malaysia 3–0. Mullan took over as Ireland captain from
Megan Frazer, who was kept out of the side through injuries. She remained captain throughout Ireland's
2018 Women's Hockey World Cup campaign, leading them to the silver medal. She featured in all of Ireland's games throughout the tournament, including the pool games against the
United States,
India, and
England, the quarter-final against India, the semi-final against
Spain and the final against the
Netherlands. ==Honours==