Until 1837, Leins attended the Friedrich-Eugens-Gymnasium in Stuttgart, then served an apprenticeship at a local architectural firm.
From 1837 to 1840, he lived in Paris, where he found employment with Henri Labrouste, while he received training from Eugène Flachat and Jules Petiet.
His work on a new building for the Russian Legation impressed the Crown Prince, so Leins was contracted to design the "Villa Berg", a new royal residence.
[2] In 1853, he undertook another study trip to Italy, Spain and North Africa with Friedrich Wilhelm Hackländer and Theodor Horschelt.
Over his career, he was involved in the construction, restoration or expansion of over 100 Protestant churches[1] In 1872, he was awarded the Knight's Cross, First Class of the Order of the Crown (Württemberg), which conferred a title of nobility.