The two-hour show, which saw Joe McElderry triumph over rival Olly Murs, averaged 15.62m (53.2%) between 7.30pm and 9.30pm, peaking with an impressive 19.7m (63.2%) when the result was announced at 9.18pm.
Last year, Alexandra Burke's victory had 13.46m (54.4%), hitting a high of 14.59m (61.4%) at 10.40pm.
Holly Willoughby-fronted spinoff show The Xtra Factor then put in 1.87m (7.6%) at 9.30pm for ITV2.
Post-X Factor on ITV1, 9.84m (38.4%) tuned in for I Dreamed A Dream: The Susan Boyle Story, which aired between 9.30pm and 10.30pm.
Over on BBC One, Sports Personality Of The Year, which aired between 7pm and 9pm, put in 4.7m (16.8%). Small Island followed immediately afterwards, bringing in 3.24m (12.1%).
A repeat of Delia's Classic Christmas grabbed 2.14m (8%) for BBC Two at 7pm, then the audience dropped to 1.73m (5.8%) during the 8pm screening of Victorian Farm Christmas.
Channel 4 repeats The Worst Christmas Jobs In History and Come Dine With Me drew 1.26m (4.4%) and 1.01m (3.3%) at 7.30pm and 8.30pm respectively, then Kal Penn film Epic Movie had 1.49m (6.5%) between 9.30pm and 11.10pm.
Raid On Entebbe managed 851k (3.1%) for Five between 6.35pm and 9.30pm, then 1.34m (6.75) watched Constantine between 9.30pm and 11.50pm.
Overall, ITV1 dominated primetime with an average share of 43.2% to BBC One's 15.1%. BBC Two was third with 7.5%, followed by Channel 4 with 6.5% (+1: 0.8%) and Five's 3.9%.
BARB ratings data supplied by Attentional