The son of a stonemason, Injalbert was a pupil of Augustin-Alexandre Dumont and won the prestigious Prix de Rome in 1874. At the Exposition Universelle of 1889 he won the Grand Prix, and in 1900 was a member of the jury. On the day of the inauguration of the Pont Mirabeau in Paris, Injalbert was made an officer of the Légion d'honneur. In 1905 he was made a member of the Institut de France, and in 1910 promoted to Commander of the Légion d'honneur.