Leidos Software Engineer Interview Questions + Guide in 2025

Leidos is a leading defense, aviation, information technology, and biomedical research company that provides solutions to complex challenges in a variety of sectors, including defense and national security.

The Software Engineer role at Leidos involves designing, developing, and testing software solutions for advanced technology projects, including those related to radar systems, signal processing, and military applications. Key responsibilities include writing efficient code in languages such as C++, Java, and Python, collaborating with cross-functional teams to integrate hardware and software, and participating in the full software development lifecycle. Candidates should exhibit strong problem-solving skills, a solid understanding of object-oriented programming principles, and experience with software development methodologies such as Agile and DevOps. Familiarity with tools like Git, Jenkins, and AWS is highly valued. Ideal candidates are also adaptable, able to communicate effectively with diverse teams, and possess a willingness to learn and grow within a dynamic work environment.

This guide will help you prepare for your job interview by providing targeted insights into the expectations and common questions associated with the Software Engineer role at Leidos, giving you a competitive edge in your candidacy.

The interview process for a Software Engineer position at Leidos is structured to assess both technical skills and cultural fit within the organization. It typically unfolds in several stages, allowing candidates to showcase their qualifications and experiences effectively.

1. Initial Phone Screen

The process begins with an initial phone screen, usually lasting about 30 minutes. This interview is conducted by a recruiter or HR representative and focuses on your resume, background, and general fit for the company. Expect to discuss your previous experiences, the technologies you are familiar with, and your interest in the role. This is also an opportunity for you to ask questions about the company culture and the specifics of the position.

2. Technical Interview

Following the initial screen, candidates may be invited to a technical interview, which can be conducted over the phone or via video conferencing. This interview typically lasts around an hour and includes a mix of technical questions related to programming languages, software development principles, and problem-solving scenarios. You may be asked to solve coding challenges or explain your approach to specific technical problems, such as algorithms or data structures.

3. Behavioral Interview

In addition to technical assessments, Leidos places significant emphasis on behavioral interviews. These interviews often occur in a panel format, where you will meet with multiple team members, including hiring managers and senior engineers. Expect questions that explore your teamwork, conflict resolution, and adaptability in various situations. The goal is to gauge how well you align with the company's values and how you handle real-world challenges in a collaborative environment.

4. Onsite Interview (or Final Round)

For candidates who progress past the initial interviews, an onsite interview may be scheduled. This stage can involve multiple rounds of interviews with different team members, including technical assessments, coding exercises, and discussions about your past projects. You may also be asked to participate in whiteboard coding sessions or system design discussions. This is a chance for you to demonstrate your technical expertise and how you approach complex engineering problems.

5. Offer and Background Check

If you successfully navigate the interview process, you may receive a job offer. However, be prepared for a background check, which is standard for positions at Leidos, especially those involving sensitive projects. The company values transparency, so it’s advisable to communicate any potential issues upfront.

As you prepare for your interviews, consider the types of questions that may arise in each of these stages, particularly those that relate to your technical skills and past experiences.

Here are some tips to help you excel in your interview.

Be Transparent About Your Work Environment

If you are accustomed to working from home, share that with your hiring manager. If not, demonstrate your flexibility and adaptability to different work circumstances. Given the current climate, where remote work policies may still be in flux, being upfront about your home setup can help manage expectations. If you anticipate any disruptions during the interview, such as a poor internet connection or background noise, proactively communicate this. Your honesty will be appreciated and can set a positive tone for the conversation.

Know Your Resume Inside and Out

Expect the interviewers to ask questions based on your resume. Be prepared to discuss your past experiences in detail, especially the projects and technologies you have worked with. Highlight your proficiency in programming languages and frameworks relevant to the role, such as C++, Python, or Java. Familiarize yourself with the specific technologies mentioned in the job description, as well as any tools you have used in your previous roles, such as Git, JIRA, or CI/CD pipelines.

Prepare for Behavioral Questions

Leidos places a strong emphasis on teamwork and collaboration. Be ready to answer behavioral questions that assess your soft skills, such as conflict resolution, teamwork, and adaptability. Use the STAR (Situation, Task, Action, Result) method to structure your responses, providing clear examples from your past experiences that demonstrate your ability to work effectively in a team environment.

Brush Up on Technical Fundamentals

While the technical questions may not be overly complex, you should still be prepared to discuss fundamental concepts related to software engineering, such as object-oriented programming (OOP), data structures, and algorithms. Review common coding challenges and practice coding problems that may be relevant to the role. Familiarize yourself with the principles of real-time systems and any specific technologies mentioned in the job description, such as signal processing or radar systems.

Engage with Your Interviewers

Leidos values candidates who show genuine interest in the company and its projects. Prepare thoughtful questions to ask your interviewers about the team dynamics, ongoing projects, and the company culture. This not only demonstrates your enthusiasm for the role but also helps you assess if Leidos is the right fit for you. Asking about the challenges the team is currently facing or the technologies they are excited about can lead to a more engaging conversation.

Emphasize Your Willingness to Learn

Given the rapidly evolving nature of technology, express your eagerness to learn and grow within the company. Highlight any experiences where you have taken the initiative to learn new skills or adapt to new technologies. This aligns well with Leidos' commitment to employee development and can set you apart as a candidate who is not only qualified but also motivated to contribute to the team's success.

Follow Up After the Interview

After your interview, send a thank-you email to express your appreciation for the opportunity to interview and reiterate your interest in the position. This small gesture can leave a lasting impression and demonstrates your professionalism and enthusiasm for the role.

By following these tips, you can present yourself as a well-rounded candidate who is not only technically proficient but also a great cultural fit for Leidos. Good luck!

In this section, we’ll review the various interview questions that might be asked during a Software Engineer interview at Leidos. The interview process will likely assess both your technical skills and your ability to work collaboratively within a team. Be prepared to discuss your past experiences, technical knowledge, and how you approach problem-solving.

Technical Skills

1. Can you explain the principles of Object-Oriented Programming (OOP) and its advantages?

Understanding OOP is crucial for software development roles, as it forms the foundation of many programming languages.

How to Answer

Discuss the four main principles: encapsulation, inheritance, polymorphism, and abstraction. Provide examples of how these principles can lead to more manageable and scalable code.

Example

“OOP is based on four main principles: encapsulation, which helps in bundling data and methods; inheritance, allowing new classes to inherit properties from existing ones; polymorphism, enabling methods to do different things based on the object; and abstraction, which simplifies complex systems by modeling classes based on essential properties. For instance, in a project I worked on, I used inheritance to create a base class for different types of user accounts, which streamlined the code and made it easier to manage.”

2. What is your experience with multithreading, and how have you implemented it in your projects?

Multithreading is essential for improving the performance of applications, especially in environments where tasks can be executed concurrently.

How to Answer

Explain your understanding of multithreading concepts and provide a specific example of how you applied it in a project.

Example

“I have implemented multithreading in several projects to enhance performance. For instance, in a data processing application, I used threads to handle multiple data streams simultaneously, which reduced processing time significantly. I ensured thread safety by using synchronization techniques to prevent data corruption.”

3. Describe your experience with real-time systems and the challenges you faced.

Real-time systems are critical in many applications, especially in defense and aerospace sectors.

How to Answer

Discuss your experience with real-time systems, the specific challenges you encountered, and how you overcame them.

Example

“I worked on a project involving real-time data acquisition for a radar system. One of the main challenges was ensuring that data was processed within strict time constraints. I implemented priority scheduling to manage tasks effectively and used real-time operating systems to meet the timing requirements.”

4. How do you approach debugging and troubleshooting in your code?

Debugging is a vital skill for any software engineer, and your approach can reveal your problem-solving abilities.

How to Answer

Outline your systematic approach to debugging, including tools and techniques you use.

Example

“When debugging, I first try to reproduce the issue consistently. I then use logging to gather more information about the state of the application. I often utilize debugging tools like GDB or IDE-integrated debuggers to step through the code. For example, in a recent project, I encountered a memory leak, and by using Valgrind, I was able to identify the source and resolve it efficiently.”

Behavioral Questions

5. Tell me about a time you faced a difficult challenge in a team project. How did you handle it?

Team dynamics are crucial in collaborative environments, and this question assesses your interpersonal skills.

How to Answer

Describe the situation, your role, the challenge, and the outcome, focusing on your contributions.

Example

“In a recent project, our team faced a significant challenge when a key member left unexpectedly. I took the initiative to redistribute the workload and organized daily check-ins to ensure everyone was aligned. By fostering open communication, we managed to meet our deadlines and even received positive feedback from our stakeholders.”

6. How do you prioritize tasks when working on multiple projects?

Effective prioritization is essential in fast-paced environments.

How to Answer

Discuss your methods for prioritizing tasks, such as using project management tools or frameworks.

Example

“I prioritize tasks based on deadlines and project impact. I use tools like JIRA to track progress and set priorities. For instance, during a busy period, I focused on high-impact features that were critical for the upcoming release while delegating less urgent tasks to team members.”

7. Describe a time when you disagreed with a teammate about a technical decision. How did you resolve it?

Conflict resolution is a key skill in collaborative environments.

How to Answer

Explain the disagreement, how you approached the discussion, and the resolution.

Example

“I once disagreed with a teammate about the choice of a database for a project. I suggested we conduct a performance analysis of both options. We presented our findings to the team, which led to a data-driven decision that everyone supported. This approach not only resolved the conflict but also strengthened our collaboration.”

8. What motivates you to work in software engineering, particularly in the defense sector?

Understanding your motivation can help interviewers gauge your fit for the company culture.

How to Answer

Share your passion for technology and how it aligns with the mission of the defense sector.

Example

“I am motivated by the challenge of solving complex problems and the opportunity to contribute to national security. Working in the defense sector allows me to apply my skills to projects that have a significant impact, and I find it rewarding to be part of a team that develops innovative solutions for critical missions.”