Over the years, placement preparation has posed serious daunting problems to most of the engineering students, such as lack of efficiency with Applicant Tracking System (ATS); limited, unrealistic practice of interviews; scattered and often obsolete resources. Such a situation results in low self-esteem, misaligned applications for jobs, and ineffective preparation. Such problems are addressed by this paper, wherein SkillSage, an AI-based platform, is developed for closing these gaps with integrated modules such as resume optimization, mock interviews, job matching, and skills assessment. SkillSage applies advanced NLP models like GPT-4, Whisper API to provide personalized feedback, adaptive learning pathways, and real-time speech-to-text simulation for interviews. ATS compliant resume scoring, skill-based job suggestions, and AI quizzes are additional features. Early evaluation results have shown considerable improvement in interview performance, acceptance of resumes, and job-skill matching accuracy. In this way, SkillSage provides the entire intelligent solution to address the gap between what academia prepares students for and what the industry expects.