Principal Machine Learning Engineer (San Jose)

The application window is expected to close on: 08/27/2026Job posting may be removed earlier if the position is filled or if a sufficient number of applications are received.Meet the TeamWe are an agile team with a startup feel and a strong bias for action. We move fast, embrace failure as part of the process, and stay focused on solving real-world problems for defenders on the front lines. Our team blends deep expertise in AI, cybersecurity, and platform engineering. We are driven by a shared belief that the only way to outpace hackers is through AI advancements that free up humans to tackle real threats and more challenging problems.This is a place for builders who thrive in ambiguity, challenge the status quo, and care deeply about making a meaningful impact. If you're energized by tough problems, excited to shape the future of cyber defense, and eager to work alongside passionate experts, you'll feel right at home.Your ImpactDesign and build agentic workflows that combine detection signals, context, and playbooks to automate threat triage and response.Prototype and test new AI features—from enrichment agents to incident summarization—working closely with Security SMEs to validate real-world utility.Develop an AIOps pipeline to enable rapid experimentation with prompts, models, and RAG systems, using clear, measurable success criteria to evaluate iterations.Evaluate model outputs for accuracy, reliability, and usability, then prototype and deploy improvements based on structured feedback and testing.Collaborate with Product and Platform teams to co-design AI-enhanced TDIR workflows that are intuitive, scalable, and immediately useful to analysts.Contribute to the core architecture powering AI-native security operations, helping shape how Splunk and Cisco scale trusted automation across the enterprise.Minimum QualificationsBachelor's degree with 12+ years of related experience, Master's degree with 7+ years of related experience, or PhD with 5+ years of related experience.Experience designing and building scalable backend services, APIs, and automation solutions using Python.Experience with Security Operations concepts, including threat detection, triage, investigation, and incident response.Experience designing, developing, and integrating AI-powered solutions using Large Language Models (LLMs), including prompt engineering, agentic AI workflows, and AI application development.Experience working with security telemetry (e.g., endpoint, network, authentication, cloud, or similar data sources) and building automation or detection workflows that leverage security data.Preferred QualificationsExperience building and integrating product APIs to automate Security Operations workflows.Experience evaluating AI model performance using structured experimentation, including accuracy, reliability, usability, latency, and cost optimization.Experience designing evaluation frameworks and experiments for LLM-based applications.Experience with SIEM and SOAR platforms, such as Splunk, from a practitioner, engineering, or automation perspective.Experience as a Tier 3 SOC Analyst, Detection Engineer, Security Automation Engineer, or similar Security Operations role.Experience developing Retrieval-Augmented Generation (RAG) applications and working with vector databases such as Pinecone, FAISS, or similar technologies.Experience with LLM fine-tuning, embedding models, or domain-specific AI customization for cybersecurity applications.Experience building scalable security data pipelines for ingesting, parsing, enriching, and normalizing high-volume security telemetry.Passion for designing intuitive AI-assisted analyst experiences with a focus on usability, explainability, trust, and human-centered design.Experience collaborating across Product Management, Engineering, and Security Research to rapidly deliver customer-focused AI capabilities.Why Cisco? At Cisco, we’re revolutionizing how data and infrastructure connect and protect organizations in the AI era – and beyond. We’ve been innovating fearlessly for 40 years to create solutions that power how humans and technology work together across the physical and digital worlds. These solutions provide customers with unparalleled security, visibility, and insights across the entire digital footprint.Fueled by the depth and breadth of our technology, we experiment and create meaningful solutions. Add to that our worldwide network of doers and experts, and you’ll see that the opportunities to grow and build are limitless. We work as a team, collaborating with empathy to make really big things happen on a global scale. Because our solutions are everywhere, our impact is everywhere. We are Cisco, and our power starts with you. Message to applicants applying to work in the U.S. and/or Canada:The starting salary range posted for this position is $291,500.00 to $369,100.00 and reflects the projected salary range for new hires in this position in U.S. and/or Canada locations, not including incentive compensation*, equity, or benefits.Individual pay is determined by the candidate's hiring location, market conditions, job-related skillset, experience, qualifications, education, certifications, and/or training. The full salary range for certain locations is listed below. For locations not listed below, the recruiter can share more details about compensation for the role in your location during the hiring process.U.S. employees are offered benefits, subject to Cisco’s plan eligibility rules, which include medical, dental and vision insurance, a 401(k) plan with a Cisco matching contribution, paid parental leave, short and long-term disability coverage, and basic life insurance. Please see the Cisco careers site to discover more benefits and perks. Employees may be eligible to receive grants of Cisco restricted stock units, which vest following continued employment with Cisco for defined periods of time.U.S. employees are eligible for paid time away as described below, subject to Cisco’s policies:10 paid holidays per full calendar year, plus 1 floating holiday for non-exempt employees1 paid day off for employee’s birthday, paid year-end holiday shutdown, and 4 paid days off for personal wellness determined by CiscoNon-exempt employees receive 16 days of paid vacation time per full calendar year, accrued at rate of 4.92 hours per pay period for full-time employeesExempt employees participate in Cisco’s flexible vacation time off program, which has no defined limit on how much vacation time eligible employees may use (subject to availability and some business limitations)80 hours of sick time off provided on hire date and each January 1st thereafter, and up to 80 hours of unused sick time carried forward from one calendar year to the nextAdditional paid time away may be requested to deal with critical or emergency issues for family membersOptional 10 paid days per full calendar year to volunteerFor non-sales roles, employees are also eligible to earn annual bonuses subject to Cisco’s policies.Employees on sales plans earn performance-based incentive pay on top of their base salary, which is split between quota and non-quota components, subject to the applicable Cisco plan. For quota-based incentive pay, Cisco typically pays as follows:.75% of incentive target for each 1% of revenue attainment up to 50% of quota;1.5% of incentive target for each 1% of attainment between 50% and 75%;1% of incentive target for each 1% of attainment between 75% and 100%; andOnce performance exceeds 100% attainment, incentive rates are at or above 1% for each 1% of attainment with no cap on incentive compensation.For non-quota-based sales performance elements such as strategic sales objectives, Cisco may pay 0% up to 125% of target. Cisco sales plans do not have a minimum threshold of performance for sales incentive compensation to be paid.The applicable full salary ranges for this position, by specific state, are listed below:New York City Metro Area:$291,500.00 - $424,400.00Non-Metro New York state & Washington state:$259,400.00 - $377,600.00* For quota-based sales roles on Cisco’s sales plan, the ranges provided in this posting include base pay and sales target incentive compensation combined. Employees in Illinois, whether exempt or non-exempt, will participate in a unique time off program to meet local requirements.Job SummaryJob number: 2020518Date posted : 2026-07-21Profession: OtherEmployment type: Full time