Chan Yuen-ting became the first female coach to win a top-flight league title with a professional men's team.
A 2-1 win over South China at the Tseung Kwan O Sports Ground saw her Eastern side crowned champions of Hong Kong for a fifth time.
In doing so, Chan became the first ever female to guide a professional men's team to a top-flight championship.
Chan, 27, only took over as coach in December, with Eastern going on to lose just once in 15 games.
The championship win also means Eastern confirmed their spot in the qualifiers for the AFC Champions League.
Eastern were also in the running to win the Hong Kong FA Cup but suffered a 1-0 defeat to Yuen Long in the quarter-finals last week.