Complex sentence: Disick first became known to reality television audiences in 2007 when he appeared in "Keeping Up With The Kardashians", since then he has appeared in the spin-off shows "Kourtney and Khloé Take Miami" and "Kourtney and Kim Take New York".
Split into simpler sentences: Disick first became known to reality television audiences in 2007 when he appeared in "Keeping Up With The Kardashians". Since then he has appeared in the spin-off shows "Kourtney and Khloé Take Miami" and "Kourtney and Kim Take New York".