Though Masachika first succeeded his father and became hatamoto, he was adopted by Masataka ABE because their head family, Shinobu clan had no successor and Masachika succeeded Masataka as the head of the family when Masataka retired in 1748.
はじめ父の後をついで旗本となるが、宗家・忍藩に後継者がいないため阿部正喬の養子となり、寛延元年（1748年）に正喬の隠居により家督を継ぐ。