  Using the reactance matrix approach, we systematically develop new
multichannel quantum defect theory models for the singlet and triplet S, P, D
and F states of strontium based on improved energy level measurements. The new
models reveal additional insights into the character of doubly excited
perturber states, and the improved energy level measurements for certain series
allow fine structure to be resolved for those series' perturbers. Comparison
between the predictions of the new models and those of previous empirical and
\emph{ab initio} studies reveals good agreement with most series, however some
discrepancies are highlighted. Using the multichannel quantum defect theory
wave functions derived from our models we calculate other observables such as
Land\'e $g_J$-factors and radiative lifetimes. The analysis reveals the impact
of perturbers on the Rydberg state properties of divalent atoms, highlighting
the importance of including two-electron effects in the calculations of these
properties. The work enables future investigations of properties such as Stark
maps and long-range interactions of Rydberg states of strontium.
