Starting a new finance role is one of the highest risk points in your career. Not because you are incapable, but because expectations are often unclear, timeframes are unrealistic, and you are expected to add value before you have full context.

This is especially true in startups and scale-ups.

You might be the first senior finance hire.
You might be stepping up from Finance Manager to Head of Finance.
You might be moving into a CFO or fractional CFO role earlier than planned.

In all of these cases, the first 90 days matter more than any other period. They shape how founders see you, what you get trusted with, and whether you are positioned as a leader or a firefighter.

A good 90-day plan is not a list of tasks, instead it is a leadership tool.

Below is what I believe every finance professional should include in a 90-day plan when starting a new role, based on what actually works in fast-growth environments.

Start With Outcomes, Not Activity

The biggest mistake finance leaders make is building a 90-day plan full of actions without being clear on the outcomes those actions are meant to achieve.

Before you think about deliverables, be clear on what success looks like by day 90.

For example:

• The founder trusts the numbers
• Cashflow visibility is clearer than it was before you joined
• Reporting is consistent and understood
• Key risks are surfaced, not hidden
• You are seen as someone who brings structure and calm

These outcomes should anchor everything else in your plan. If an activity does not move you closer to one of these, it is probably noise.

Days 1–30: Understand Before You Fix

The first 30 days are about learning, not proving yourself.

This is where many finance professionals overcorrect. They feel pressure to add value quickly, so they start changing things before they fully understand the business. That often backfires.

Your focus in the first month should be:

1. Understanding the business model

You need to know how the business actually makes money, not how it is described in the pitch deck.

• What drives revenue
• What drives cost
• Where cash really leaks
• What assumptions the founder is relying on

If you don’t understand this, everything else is cosmetic.

2. Assessing the current finance foundations

This is not about judging but getting the full picture.

Look at:

• Bookkeeping quality
• Month end process
• Reporting cadence
• Cashflow visibility
• Tools and tech stack
• Who owns what

You are building a mental map of what exists and where the real risks are.

3. Building relationships and trust

Your influence later depends on the trust you build early.

Spend time with:

• The founder
• Key operational leads
• Anyone touching numbers

Ask questions. Listen carefully. Avoid criticism. You are gathering context.

Your output at the end of the first 30 days should be a clear assessment, not a long to-do list.

Days 31–60: Stabilise and Create Early Wins

The second 30 days are about creating stability and credibility, both for your self and your team.

At this stage, people want to see movement. The key is choosing the right movement.

1. Fix what is blocking decision-making

Do not try to fix everything. Focus on what is preventing the business from making better decisions right now.  That might be:

• Unreliable cashflow forecasting
• Confusing or inconsistent reporting
• No clarity on runway
• Poor visibility of key costs

These are high-impact areas that demonstrate leadership quickly.

2. Clarify what “good” looks like

Many founders have never worked with a senior finance leader before. They do not know what to expect.  I will go into this topic in more detail over the next 2 weeks.  

Use this period to:

• Define what month end should look like
• Set expectations on timelines and quality
• Explain what finance can and cannot do

This avoids misalignment later.

3. Deliver one visible improvement

Early wins matter, but they should be meaningful.  Examples:

• A clearer cash view
• A simplified P&L
• A cleaner reporting pack
• A short risk summary

This shows you are not just observing but you are making considered changes.

Days 61–90: Position Yourself as a Leader

The final 30 days are about shifting how you are perceived.

By now, you should understand the business and have delivered something tangible. This is where you start stepping fully into a leadership role.

1. Move from reporting to insight

Stop being the person who just produces numbers.  Start being the person who explains:

• What is happening
• Why it is happening
• What decisions need to be made

This is where finance becomes a strategic function.

2. Introduce forward-looking thinking

In startups especially, looking backwards is not enough.  This is the time to:

• Introduce scenarios
• Improve forecasting discipline
• Link numbers to operational decisions  (what are the operational goals?)

Even lightweight improvements here can change how finance is viewed.

3. Set the roadmap beyond 90 days

Your 90-day plan should end with a clear view of what comes next.  Not a massive transformation plan but just a defined roadmap.

It should include:

• What needs to be fixed next
• What can wait
• Where investment is needed
• Where you need support

This shows maturity and builds confidence in your leadership.

Don’t Forget the Personal Side

A 90-day plan is not just about the business. It is also about you.  Ask yourself:

Where do I need to build confidence?

What skills do I need to develop to succeed here?

What support will I need?

Many finance professionals struggle in new roles not because they lack ability, but because imposter syndrome quietly drives their behaviour. A good plan acknowledges this and builds resilience alongside delivery.

Want to become a confident, strategic finance leader in a startup within the next 12 months? 

Here’s your plan:

1. Subscribe to my YouTube channel and Newsletter for weekly practical tips and real talk about startup finance leadership.
2. Read my book Financial Leadership Fundamentals to get clear on what’s expected of you and how to show up as a leader.
3. Join the Financial Leadership Fundamentals course to fast-track your growth with structure, support, and strategy that works in the real world.