The present work reports a photophysical study of norfloxacin (NOF), an efficient chemotherapeutic antibacterial drug, in well-characterized biomimetic micellar aggregates of anionic surfactants. The major focus of the present investigation lies in deciphering the effect of the surfactant chain length on the structural dynamics of the drug within a micelle-encapsulated state through steady-state and time-resolved fluorescence spectroscopic techniques. The anionic surfactants employed for the purpose are decyl sodium sulfate (S10S), dodecyl sodium sulfate (S12S) and tetradecyl sodium sulfate (S14S). Our experimental results evince that increasing hydrophobic surfactant tail length exerts a profound influence on promoting a specific prototropic form of NOF within the micellar aggregates; an apparently enigmatic observation is that increasing hydrophobicity of the micellar microheterogeneous system indeed favors the cationic species of the drug. This is interpreted on the basis of electrostatic stabilization between the drug (cationic form) and anionic surface charge of the as-employed micellar assemblies, while the micellar hydration model fails to rationalize the experimental findings. Particular emphasis is also given on delineating the probable location and the modulated rotational-relaxation dynamics of the drug molecule within the micellar aggregates. The interaction thermodynamics and dynamics of norfloxacin within anionic micelles is critically dependent on the tail length of the surfactant such that the micellar hydration model is found to be inadequate to explain the photophysics of the drug whereas electrostatic interaction appears to play the governing role.